• squid源码安装下的conf文件默认值和提示



    #    WELCOME TO SQUID 3.0.STABLE26
    #    ----------------------------
    #
    #    This is the default Squid configuration file. You may wish
    #    to look at the Squid home page (http://www.squid-cache.org/)
    #    for the FAQ and other documentation.
    #
    #    The default Squid config file shows what the defaults for
    #    various options happen to be.  If you don't need to change the
    #    default, you shouldn't uncomment the line.  Doing so may cause
    #    run-time problems.  In some cases "none" refers to no default
    #    setting at all, while in other cases it refers to a valid
    #    option - the comments for that keyword indicate if this is the
    #    case.
    #


    #  Configuration options can be included using the "include" directive.
    #  Include takes a list of files to include. Quoting and wildcards is
    #  supported.
    #
    #  For example,
    #
    #  include /path/to/included/file/squid.acl.config
    #
    #  Includes can be nested up to a hard-coded depth of 16 levels.
    #  This arbitrary restriction is to prevent recursive include references
    #  from causing Squid entering an infinite loop whilst trying to load
    #  configuration files.


    # OPTIONS FOR AUTHENTICATION
    # -----------------------------------------------------------------------------

    #  TAG: auth_param
    #    This is used to define parameters for the various authentication
    #    schemes supported by Squid.
    #
    #    format: auth_param scheme parameter [setting]
    #
    #    The order in which authentication schemes are presented to the client is
    #    dependent on the order the scheme first appears in config file. IE
    #    has a bug (it's not RFC 2617 compliant) in that it will use the basic
    #    scheme if basic is the first entry presented, even if more secure
    #    schemes are presented. For now use the order in the recommended
    #    settings section below. If other browsers have difficulties (don't
    #    recognize the schemes offered even if you are using basic) either
    #    put basic first, or disable the other schemes (by commenting out their
    #    program entry).
    #
    #    Once an authentication scheme is fully configured, it can only be
    #    shutdown by shutting squid down and restarting. Changes can be made on
    #    the fly and activated with a reconfigure. I.E. You can change to a
    #    different helper, but not unconfigure the helper completely.
    #
    #    Please note that while this directive defines how Squid processes
    #    authentication it does not automatically activate authentication.
    #    To use authentication you must in addition make use of ACLs based
    #    on login name in http_access (proxy_auth, proxy_auth_regex or
    #    external with %LOGIN used in the format tag). The browser will be
    #    challenged for authentication on the first such acl encountered
    #    in http_access processing and will also be re-challenged for new
    #    login credentials if the request is being denied by a proxy_auth
    #    type acl.
    #
    #    WARNING: authentication can't be used in a transparently intercepting
    #    proxy as the client then thinks it is talking to an origin server and
    #    not the proxy. This is a limitation of bending the TCP/IP protocol to
    #    transparently intercepting port 80, not a limitation in Squid.
    #    Ports flagged 'transparent' or 'tproxy' have authentication disabled.
    #
    #    === Parameters for the basic scheme follow. ===
    #
    #    "program" cmdline
    #    Specify the command for the external authenticator.  Such a program
    #    reads a line containing "username password" and replies "OK" or
    #    "ERR" in an endless loop. "ERR" responses may optionally be followed
    #    by a error description available as %m in the returned error page.
    #    If you use an authenticator, make sure you have 1 acl of type proxy_auth.
    #
    #    By default, the basic authentication scheme is not used unless a
    #    program is specified.
    #
    #    If you want to use the traditional NCSA proxy authentication, set
    #    this line to something like
    #
    #    auth_param basic program /usr/local/squid3.0/libexec/ncsa_auth /usr/local/squid3.0/etc/passwd
    #
    #    "children" numberofchildren
    #    The number of authenticator processes to spawn. If you start too few
    #    Squid will have to wait for them to process a backlog of credential
    #    verifications, slowing it down. When password verifications are
    #    done via a (slow) network you are likely to need lots of
    #    authenticator processes.
    #    auth_param basic children 5
    #
    #    "concurrency" concurrency
    #    The number of concurrent requests the helper can process.
    #    The default of 0 is used for helpers who only supports
    #    one request at a time. Setting this changes the protocol used to
    #    include a channel number first on the request/response line, allowing
    #    multiple requests to be sent to the same helper in parallell without
    #    wating for the response.
    #    Must not be set unless it's known the helper supports this.
    #    auth_param basic concurrency 0
    #
    #    "realm" realmstring
    #    Specifies the realm name which is to be reported to the
    #    client for the basic proxy authentication scheme (part of
    #    the text the user will see when prompted their username and
    #    password). There is no default.
    #    auth_param basic realm Squid proxy-caching web server
    #
    #    "credentialsttl" timetolive
    #    Specifies how long squid assumes an externally validated
    #    username:password pair is valid for - in other words how
    #    often the helper program is called for that user. Set this
    #    low to force revalidation with short lived passwords.  Note
    #    setting this high does not impact your susceptibility
    #    to replay attacks unless you are using an one-time password
    #    system (such as SecureID).  If you are using such a system,
    #    you will be vulnerable to replay attacks unless you also
    #    use the max_user_ip ACL in an http_access rule.
    #
    #    "casesensitive" on|off
    #    Specifies if usernames are case sensitive. Most user databases are
    #    case insensitive allowing the same username to be spelled using both
    #    lower and upper case letters, but some are case sensitive. This
    #    makes a big difference for user_max_ip ACL processing and similar.
    #    auth_param basic casesensitive off
    #
    #    === Parameters for the digest scheme follow ===
    #
    #    "program" cmdline
    #    Specify the command for the external authenticator.  Such
    #    a program reads a line containing "username":"realm" and
    #    replies with the appropriate H(A1) value hex encoded or
    #    ERR if the user (or his H(A1) hash) does not exists.
    #    See rfc 2616 for the definition of H(A1).
    #    "ERR" responses may optionally be followed by a error description
    #    available as %m in the returned error page.
    #
    #    By default, the digest authentication scheme is not used unless a
    #    program is specified.
    #
    #    If you want to use a digest authenticator, set this line to
    #    something like
    #
    #    auth_param digest program /usr/local/squid3.0/bin/digest_pw_auth /usr/local/squid3.0/etc/digpass
    #
    #    "children" numberofchildren
    #    The number of authenticator processes to spawn (no default).
    #    If you start too few Squid will have to wait for them to
    #    process a backlog of H(A1) calculations, slowing it down.
    #    When the H(A1) calculations are done via a (slow) network
    #    you are likely to need lots of authenticator processes.
    #    auth_param digest children 5
    #
    #    "realm" realmstring
    #    Specifies the realm name which is to be reported to the
    #    client for the digest proxy authentication scheme (part of
    #    the text the user will see when prompted their username and
    #    password). There is no default.
    #    auth_param digest realm Squid proxy-caching web server
    #
    #    "nonce_garbage_interval" timeinterval
    #    Specifies the interval that nonces that have been issued
    #    to client_agent's are checked for validity.
    #
    #    "nonce_max_duration" timeinterval
    #    Specifies the maximum length of time a given nonce will be
    #    valid for.
    #
    #    "nonce_max_count" number
    #    Specifies the maximum number of times a given nonce can be
    #    used.
    #
    #    "nonce_strictness" on|off
    #    Determines if squid requires strict increment-by-1 behavior
    #    for nonce counts, or just incrementing (off - for use when
    #    useragents generate nonce counts that occasionally miss 1
    #    (ie, 1,2,4,6)). Default off.
    #
    #    "check_nonce_count" on|off
    #    This directive if set to off can disable the nonce count check
    #    completely to work around buggy digest qop implementations in
    #    certain mainstream browser versions. Default on to check the
    #    nonce count to protect from authentication replay attacks.
    #
    #    "post_workaround" on|off
    #    This is a workaround to certain buggy browsers who sends
    #    an incorrect request digest in POST requests when reusing
    #    the same nonce as acquired earlier on a GET request.
    #
    #    === NTLM scheme options follow ===
    #
    #    "program" cmdline
    #    Specify the command for the external NTLM authenticator.
    #    Such a program reads exchanged NTLMSSP packets with
    #    the browser via Squid until authentication is completed.
    #    If you use an NTLM authenticator, make sure you have 1 acl
    #    of type proxy_auth.  By default, the NTLM authenticator_program
    #    is not used.
    #
    #    auth_param ntlm program /usr/local/squid3.0/bin/ntlm_auth
    #
    #    "children" numberofchildren
    #    The number of authenticator processes to spawn (no default).
    #    If you start too few Squid will have to wait for them to
    #    process a backlog of credential verifications, slowing it
    #    down. When credential verifications are done via a (slow)
    #    network you are likely to need lots of authenticator
    #    processes.
    #
    #    auth_param ntlm children 5
    #
    #    "keep_alive" on|off
    #    If you experience problems with PUT/POST requests when using the
    #    Negotiate authentication scheme then you can try setting this to
    #    off. This will cause Squid to forcibly close the connection on
    #    the initial requests where the browser asks which schemes are
    #    supported by the proxy.
    #
    #    auth_param ntlm keep_alive on
    #
    #    === Options for configuring the NEGOTIATE auth-scheme follow ===
    #
    #    "program" cmdline
    #    Specify the command for the external Negotiate authenticator.
    #    This protocol is used in Microsoft Active-Directory enabled setups with
    #    the Microsoft Internet Explorer or Mozilla Firefox browsers.
    #    Its main purpose is to exchange credentials with the Squid proxy
    #    using the Kerberos mechanisms.
    #    If you use a Negotiate authenticator, make sure you have at least one acl
    #    of type proxy_auth active.  By default, the negotiate authenticator_program
    #    is not used.
    #    The only supported program for this role is the ntlm_auth
    #    program distributed as part of Samba, version 4 or later.
    #
    #    auth_param negotiate program /usr/local/squid3.0/bin/ntlm_auth --helper-protocol=gss-spnego
    #
    #    "children" numberofchildren
    #    The number of authenticator processes to spawn (no default).
    #    If you start too few Squid will have to wait for them to
    #    process a backlog of credential verifications, slowing it
    #    down. When crendential verifications are done via a (slow)
    #    network you are likely to need lots of authenticator
    #    processes.
    #    auth_param negotiate children 5
    #
    #    "keep_alive" on|off
    #    If you experience problems with PUT/POST requests when using the
    #    Negotiate authentication scheme then you can try setting this to
    #    off. This will cause Squid to forcibly close the connection on
    #    the initial requests where the browser asks which schemes are
    #    supported by the proxy.
    #
    #    auth_param negotiate keep_alive on
    #
    #Recommended minimum configuration per scheme:
    #auth_param negotiate program <uncomment and complete this line to activate>
    #auth_param negotiate children 5
    #auth_param negotiate keep_alive on
    #auth_param ntlm program <uncomment and complete this line to activate>
    #auth_param ntlm children 5
    #auth_param ntlm keep_alive on
    #auth_param digest program <uncomment and complete this line>
    #auth_param digest children 5
    #auth_param digest realm Squid proxy-caching web server
    #auth_param digest nonce_garbage_interval 5 minutes
    #auth_param digest nonce_max_duration 30 minutes
    #auth_param digest nonce_max_count 50
    #auth_param basic program <uncomment and complete this line>
    #auth_param basic children 5
    #auth_param basic realm Squid proxy-caching web server
    #auth_param basic credentialsttl 2 hours

    #  TAG: authenticate_cache_garbage_interval
    #    The time period between garbage collection across the username cache.
    #    This is a tradeoff between memory utilization (long intervals - say
    #    2 days) and CPU (short intervals - say 1 minute). Only change if you
    #    have good reason to.
    #
    #Default:
    # authenticate_cache_garbage_interval 1 hour

    #  TAG: authenticate_ttl
    #    The time a user & their credentials stay in the logged in
    #    user cache since their last request. When the garbage
    #    interval passes, all user credentials that have passed their
    #    TTL are removed from memory.
    #
    #Default:
    # authenticate_ttl 1 hour

    #  TAG: authenticate_ip_ttl
    #    If you use proxy authentication and the 'max_user_ip' ACL,
    #    this directive controls how long Squid remembers the IP
    #    addresses associated with each user.  Use a small value
    #    (e.g., 60 seconds) if your users might change addresses
    #    quickly, as is the case with dialups.   You might be safe
    #    using a larger value (e.g., 2 hours) in a corporate LAN
    #    environment with relatively static address assignments.
    #
    #Default:
    # authenticate_ip_ttl 0 seconds


    # ACCESS CONTROLS
    # -----------------------------------------------------------------------------

    #  TAG: external_acl_type
    #    This option defines external acl classes using a helper program
    #    to look up the status
    #
    #      external_acl_type name [options] FORMAT.. /path/to/helper [helper arguments..]
    #
    #    Options:
    #
    #      ttl=n        TTL in seconds for cached results (defaults to 3600
    #              for 1 hour)
    #      negative_ttl=n
    #              TTL for cached negative lookups (default same
    #              as ttl)
    #      children=n    Number of acl helper processes spawn to service
    #            external acl lookups of this type. (default 5)
    #      concurrency=n    concurrency level per process. Only used with helpers
    #            capable of processing more than one query at a time.
    #      cache=n    result cache size, 0 is unbounded (default)
    #      grace=n    Percentage remaining of TTL where a refresh of a
    #            cached entry should be initiated without needing to
    #            wait for a new reply. (default 0 for no grace period)
    #      protocol=2.5    Compatibility mode for Squid-2.5 external acl helpers
    #
    #    FORMAT specifications
    #
    #      %LOGIN    Authenticated user login name
    #      %EXT_USER    Username from external acl
    #      %IDENT    Ident user name
    #      %SRC        Client IP
    #      %SRCPORT    Client source port
    #      %URI        Requested URI
    #      %DST        Requested host
    #      %PROTO    Requested protocol
    #      %PORT        Requested port
    #      %PATH        Requested URL path
    #      %METHOD    Request method
    #      %MYADDR    Squid interface address
    #      %MYPORT    Squid http_port number
    #      %PATH        Requested URL-path (including query-string if any)
    #      %USER_CERT    SSL User certificate in PEM format
    #      %USER_CERTCHAIN SSL User certificate chain in PEM format
    #      %USER_CERT_xx    SSL User certificate subject attribute xx
    #      %USER_CA_xx    SSL User certificate issuer attribute xx
    #      %{Header}    HTTP request header "Header"
    #      %{Hdr:member}    HTTP request header "Hdr" list member "member"
    #      %{Hdr:;member}
    #              HTTP request header list member using ; as
    #              list separator. ; can be any non-alphanumeric
    #            character.
    #
    #    In addition to the above, any string specified in the referencing
    #    acl will also be included in the helper request line, after the
    #    specified formats (see the "acl external" directive)
    #
    #    The helper receives lines per the above format specification,
    #    and returns lines starting with OK or ERR indicating the validity
    #    of the request and optionally followed by additional keywords with
    #    more details.
    #
    #    General result syntax:
    #
    #      OK/ERR keyword=value ...
    #
    #    Defined keywords:
    #
    #      user=        The users name (login)
    #      password=    The users password (for login= cache_peer option)
    #      message=    Message describing the reason. Available as %o
    #              in error pages
    #      tag=        Apply a tag to a request (for both ERR and OK results)
    #              Only sets a tag, does not alter existing tags.
    #      log=        String to be logged in access.log. Available as
    #              %ea in logformat specifications
    #
    #    If protocol=3.0 (the default) then URL escaping is used to protect
    #    each value in both requests and responses.
    #
    #    If using protocol=2.5 then all values need to be enclosed in quotes
    #    if they may contain whitespace, or the whitespace escaped using .
    #    And quotes or characters within the keyword value must be escaped.
    #
    #    When using the concurrency= option the protocol is changed by
    #    introducing a query channel tag infront of the request/response.
    #    The query channel tag is a number between 0 and concurrency-1.
    #
    #Default:
    # none

    #  TAG: acl
    #    Defining an Access List
    #
    #    Every access list definition must begin with an aclname and acltype,
    #    followed by either type-specific arguments or a quoted filename that
    #    they are read from.
    #
    #       acl aclname acltype argument ...
    #       acl aclname acltype "file" ...
    #
    #    When using "file", the file should contain one item per line.
    #
    #    By default, regular expressions are CASE-SENSITIVE.  To make
    #    them case-insensitive, use the -i option.
    #
    #
    #    ***** ACL TYPES AVAILABLE *****
    #
    #    acl aclname src ip-address/netmask ...        # clients IP address
    #    acl aclname src addr1-addr2/netmask ...        # range of addresses
    #    acl aclname dst ip-address/netmask ...        # URL host's IP address
    #    acl aclname myip ip-address/netmask ...        # local socket IP address
    #
    #    acl aclname arp      mac-address ... (xx:xx:xx:xx:xx:xx notation)
    #      # The arp ACL requires the special configure option --enable-arp-acl.
    #      # Furthermore, the ARP ACL code is not portable to all operating systems.
    #      # It works on Linux, Solaris, Windows, FreeBSD, and some other *BSD variants.
    #      #
    #      # NOTE: Squid can only determine the MAC address for clients that are on
    #      # the same subnet. If the client is on a different subnet, then Squid cannot
    #      # find out its MAC address.
    #
    #    acl aclname srcdomain   .foo.com ...        # reverse lookup, from client IP
    #    acl aclname dstdomain   .foo.com ...        # Destination server from URL
    #    acl aclname srcdom_regex [-i] .foo.com ...    # regex matching client name
    #    acl aclname dstdom_regex [-i] .foo.com ...    # regex matching server
    #      # For dstdomain and dstdom_regex a reverse lookup is tried if a IP
    #      # based URL is used and no match is found. The name "none" is used
    #      # if the reverse lookup fails.
    #
    #    acl aclname src_as number ...
    #    acl aclname dst_as number ...
    #      # Except for access control, AS numbers can be used for
    #      # routing of requests to specific caches. Here's an
    #      # example for routing all requests for AS#1241 and only
    #      # those to mycache.mydomain.net:
    #      # acl asexample dst_as 1241
    #      # cache_peer_access mycache.mydomain.net allow asexample
    #      # cache_peer_access mycache_mydomain.net deny all
    #
    #    acl aclname time [day-abbrevs] [h1:m1-h2:m2]
    #      #  day-abbrevs:
    #      #    S - Sunday
    #      #    M - Monday
    #      #    T - Tuesday
    #      #    W - Wednesday
    #      #    H - Thursday
    #      #    F - Friday
    #      #    A - Saturday
    #      #  h1:m1 must be less than h2:m2
    #
    #    acl aclname url_regex [-i] ^http:// ...        # regex matching on whole URL
    #    acl aclname urlpath_regex [-i] .gif$ ...    # regex matching on URL path
    #
    #    acl aclname port 80 70 21 ...
    #    acl aclname port 0-1024 ...        # ranges allowed
    #    acl aclname myport 3128 ...        # (local socket TCP port)
    #    acl aclname myportname 3128 ...        # http(s)_port name
    #
    #    acl aclname proto HTTP FTP ...
    #
    #    acl aclname method GET POST ...
    #
    #    acl aclname http_status 200 301 500- 400-403 ...     # status code in reply
    #
    #    acl aclname browser [-i] regexp ...
    #      # pattern match on User-Agent header (see also req_header below)
    #
    #    acl aclname referer_regex [-i] regexp ...
    #      # pattern match on Referer header
    #      # Referer is highly unreliable, so use with care
    #
    #    acl aclname ident username ...
    #    acl aclname ident_regex [-i] pattern ...
    #      # string match on ident output.
    #      # use REQUIRED to accept any non-null ident.
    #
    #    acl aclname proxy_auth [-i] username ...
    #    acl aclname proxy_auth_regex [-i] pattern ...
    #      # list of valid usernames
    #      # use REQUIRED to accept any valid username.
    #      #
    #      # NOTE: when a Proxy-Authentication header is sent but it is not
    #      # needed during ACL checking the username is NOT logged
    #      # in access.log.
    #      #
    #      # NOTE: proxy_auth requires a EXTERNAL authentication program
    #      # to check username/password combinations (see
    #      # auth_param directive).
    #      #
    #      # NOTE: proxy_auth can't be used in a transparent/intercepting proxy
    #      # as the browser needs to be configured for using a proxy in order
    #      # to respond to proxy authentication.
    #
    #    acl aclname snmp_community string ...
    #      # A community string to limit access to your SNMP Agent
    #      # Example:
    #      #
    #      #    acl snmppublic snmp_community public
    #
    #    acl aclname maxconn number
    #      # This will be matched when the client's IP address has
    #      # more than <number> HTTP connections established.
    #
    #    acl aclname max_user_ip [-s] number
    #      # This will be matched when the user attempts to log in from more
    #      # than <number> different ip addresses. The authenticate_ip_ttl
    #      # parameter controls the timeout on the ip entries.
    #      # If -s is specified the limit is strict, denying browsing
    #      # from any further IP addresses until the ttl has expired. Without
    #      # -s Squid will just annoy the user by "randomly" denying requests.
    #      # (the counter is reset each time the limit is reached and a
    #      # request is denied)
    #      # NOTE: in acceleration mode or where there is mesh of child proxies,
    #      # clients may appear to come from multiple addresses if they are
    #      # going through proxy farms, so a limit of 1 may cause user problems.
    #
    #    acl aclname req_mime_type [-i] mime-type ...
    #      # regex match against the mime type of the request generated
    #      # by the client. Can be used to detect file upload or some
    #      # types HTTP tunneling requests.
    #      # NOTE: This does NOT match the reply. You cannot use this
    #      # to match the returned file type.
    #
    #    acl aclname req_header header-name [-i] any.regex.here
    #      # regex match against any of the known request headers.  May be
    #      # thought of as a superset of "browser", "referer" and "mime-type"
    #      # ACLs.
    #
    #    acl aclname rep_mime_type [-i] mime-type ...
    #      # regex match against the mime type of the reply received by
    #      # squid. Can be used to detect file download or some
    #      # types HTTP tunneling requests.
    #      # NOTE: This has no effect in http_access rules. It only has
    #      # effect in rules that affect the reply data stream such as
    #      # http_reply_access.
    #
    #    acl aclname rep_header header-name [-i] any.regex.here
    #      # regex match against any of the known reply headers. May be
    #      # thought of as a superset of "browser", "referer" and "mime-type"
    #      # ACLs.
    #
    #    acl aclname external class_name [arguments...]
    #      # external ACL lookup via a helper class defined by the
    #      # external_acl_type directive.
    #
    #    acl aclname user_cert attribute values...
    #      # match against attributes in a user SSL certificate
    #      # attribute is one of DN/C/O/CN/L/ST
    #
    #    acl aclname ca_cert attribute values...
    #      # match against attributes a users issuing CA SSL certificate
    #      # attribute is one of DN/C/O/CN/L/ST
    #
    #    acl aclname ext_user username ...
    #    acl aclname ext_user_regex [-i] pattern ...
    #      # string match on username returned by external acl helper
    #      # use REQUIRED to accept any non-null user name.
    #
    #Examples:
    #acl macaddress arp 09:00:2b:23:45:67
    #acl myexample dst_as 1241
    #acl password proxy_auth REQUIRED
    #acl fileupload req_mime_type -i ^multipart/form-data$
    #acl javascript rep_mime_type -i ^application/x-javascript$
    #
    #Default:
    # acl all src all
    #
    #Recommended minimum configuration:
    acl manager proto cache_object
    acl localhost src 127.0.0.1/32
    acl to_localhost dst 127.0.0.0/8 0.0.0.0/32
    #
    # Example rule allowing access from your local networks.
    # Adapt to list your (internal) IP networks from where browsing
    # should be allowed
    acl localnet src 10.0.0.0/8    # RFC1918 possible internal network
    acl localnet src 172.16.0.0/12    # RFC1918 possible internal network
    acl localnet src 192.168.0.0/16    # RFC1918 possible internal network
    #
    acl SSL_ports port 443
    acl Safe_ports port 80        # http
    acl Safe_ports port 21        # ftp
    acl Safe_ports port 443        # https
    acl Safe_ports port 70        # gopher
    acl Safe_ports port 210        # wais
    acl Safe_ports port 1025-65535    # unregistered ports
    acl Safe_ports port 280        # http-mgmt
    acl Safe_ports port 488        # gss-http
    acl Safe_ports port 591        # filemaker
    acl Safe_ports port 777        # multiling http
    acl CONNECT method CONNECT

    #  TAG: http_access
    #    Allowing or Denying access based on defined access lists
    #
    #    Access to the HTTP port:
    #    http_access allow|deny [!]aclname ...
    #
    #    NOTE on default values:
    #
    #    If there are no "access" lines present, the default is to deny
    #    the request.
    #
    #    If none of the "access" lines cause a match, the default is the
    #    opposite of the last line in the list.  If the last line was
    #    deny, the default is allow.  Conversely, if the last line
    #    is allow, the default will be deny.  For these reasons, it is a
    #    good idea to have an "deny all" entry at the end of your access
    #    lists to avoid potential confusion.
    #
    #Default:
    # http_access deny all
    #
    #Recommended minimum configuration:
    #
    # Only allow cachemgr access from localhost
    http_access allow manager localhost
    http_access deny manager
    # Deny requests to unknown ports
    http_access deny !Safe_ports
    # Deny CONNECT to other than SSL ports
    http_access deny CONNECT !SSL_ports
    #
    # We strongly recommend the following be uncommented to protect innocent
    # web applications running on the proxy server who think the only
    # one who can access services on "localhost" is a local user
    #http_access deny to_localhost
    #
    # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS

    # Example rule allowing access from your local networks.
    # Adapt localnet in the ACL section to list your (internal) IP networks
    # from where browsing should be allowed
    http_access allow localnet

    # And finally deny all other access to this proxy
    http_access deny all

    #  TAG: http_reply_access
    #    Allow replies to client requests. This is complementary to http_access.
    #
    #    http_reply_access allow|deny [!] aclname ...
    #
    #    NOTE: if there are no access lines present, the default is to allow
    #    all replies
    #
    #    If none of the access lines cause a match the opposite of the
    #    last line will apply. Thus it is good practice to end the rules
    #    with an "allow all" or "deny all" entry.
    #
    #Default:
    # none

    #  TAG: icp_access
    #    Allowing or Denying access to the ICP port based on defined
    #    access lists
    #
    #    icp_access  allow|deny [!]aclname ...
    #
    #    See http_access for details
    #
    #Default:
    # icp_access deny all
    #
    #Allow ICP queries from local networks only
    icp_access allow localnet
    icp_access deny all

    #  TAG: htcp_access
    #    Allowing or Denying access to the HTCP port based on defined
    #    access lists
    #
    #    htcp_access  allow|deny [!]aclname ...
    #
    #    See http_access for details
    #
    #    NOTE: The default if no htcp_access lines are present is to
    #    deny all traffic. This default may cause problems with peers
    #    using the htcp or htcp-oldsquid options.
    #
    #Default:
    # htcp_access deny all
    #
    #Allow HTCP queries from local networks only
    htcp_access allow localnet
    htcp_access deny all

    #  TAG: htcp_clr_access
    #    Allowing or Denying access to purge content using HTCP based
    #    on defined access lists
    #
    #    htcp_clr_access  allow|deny [!]aclname ...
    #
    #    See http_access for details
    #
    ##Allow HTCP CLR requests from trusted peers
    #acl htcp_clr_peer src 172.16.1.2
    #htcp_clr_access allow htcp_clr_peer
    #
    #Default:
    # htcp_clr_access deny all

    #  TAG: miss_access
    #    Use to force your neighbors to use you as a sibling instead of
    #    a parent.  For example:
    #
    #        acl localclients src 172.16.0.0/16
    #        miss_access allow localclients
    #        miss_access deny  !localclients
    #
    #    This means only your local clients are allowed to fetch
    #    MISSES and all other clients can only fetch HITS.
    #
    #    By default, allow all clients who passed the http_access rules
    #    to fetch MISSES from us.
    #
    #Default setting:
    # miss_access allow all

    #  TAG: ident_lookup_access
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-ident-lookups option
    #
    #    A list of ACL elements which, if matched, cause an ident
    #    (RFC 931) lookup to be performed for this request.  For
    #    example, you might choose to always perform ident lookups
    #    for your main multi-user Unix boxes, but not for your Macs
    #    and PCs.  By default, ident lookups are not performed for
    #    any requests.
    #
    #    To enable ident lookups for specific client addresses, you
    #    can follow this example:
    #
    #    acl ident_aware_hosts src 198.168.1.0/255.255.255.0
    #    ident_lookup_access allow ident_aware_hosts
    #    ident_lookup_access deny all
    #
    #    Only src type ACL checks are fully supported.  A src_domain
    #    ACL might work at times, but it will not always provide
    #    the correct result.
    #
    #Default:
    # ident_lookup_access deny all

    #  TAG: reply_body_max_size    size [acl acl...]
    #    This option specifies the maximum size of a reply body. It can be
    #    used to prevent users from downloading very large files, such as
    #    MP3's and movies. When the reply headers are received, the
    #    reply_body_max_size lines are processed, and the first line where
    #    all (if any) listed ACLs are true is used as the maximum body size
    #    for this reply.
    #
    #    This size is checked twice. First when we get the reply headers,
    #    we check the content-length value.  If the content length value exists
    #    and is larger than the allowed size, the request is denied and the
    #    user receives an error message that says "the request or reply
    #    is too large." If there is no content-length, and the reply
    #    size exceeds this limit, the client's connection is just closed
    #    and they will receive a partial reply.
    #
    #    WARNING: downstream caches probably can not detect a partial reply
    #    if there is no content-length header, so they will cache
    #    partial responses and give them out as hits.  You should NOT
    #    use this option if you have downstream caches.
    #
    #    WARNING: A maximum size smaller than the size of squid's error messages
    #    will cause an infinite loop and crash squid. Ensure that the smallest
    #    non-zero value you use is greater that the maximum header size plus
    #    the size of your largest error page.
    #
    #    If you set this parameter none (the default), there will be
    #    no limit imposed.
    #
    #    Configuration Format is:
    #        reply_body_max_size SIZE UNITS [acl ...]
    #    ie.
    #        reply_body_max_size 10 MB
    #
    #
    #Default:
    # none


    # NETWORK OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: http_port
    #    Usage:    port [options]
    #        hostname:port [options]
    #        1.2.3.4:port [options]
    #
    #    The socket addresses where Squid will listen for HTTP client
    #    requests.  You may specify multiple socket addresses.
    #    There are three forms: port alone, hostname with port, and
    #    IP address with port.  If you specify a hostname or IP
    #    address, Squid binds the socket to that specific
    #    address.  This replaces the old 'tcp_incoming_address'
    #    option.  Most likely, you do not need to bind to a specific
    #    address, so you can use the port number alone.
    #
    #    If you are running Squid in accelerator mode, you
    #    probably want to listen on port 80 also, or instead.
    #
    #    The -a command line option may be used to specify additional
    #    port(s) where Squid listens for proxy request. Such ports will
    #    be plain proxy ports with no options.
    #
    #    You may specify multiple socket addresses on multiple lines.
    #
    #    Options:
    #
    #       transparent    Support for transparent interception of
    #            outgoing requests without browser settings.
    #            NP: disables authentication on the port.
    #
    #       tproxy    Support Linux TPROXY for spoofing outgoing
    #            connections using the client IP address.
    #            NP: disables authentication on the port.
    #
    #       accel    Accelerator mode. Also needs at least one of
    #            vhost / vport / defaultsite.
    #
    #       defaultsite=domainname
    #            What to use for the Host: header if it is not present
    #            in a request. Determines what site (not origin server)
    #            accelerators should consider the default.
    #            Implies accel.
    #
    #       vhost    Accelerator mode using Host header for virtual
    #            domain support. Implies accel.
    #
    #       vport    Accelerator with IP based virtual host support.
    #            Implies accel.
    #
    #       vport=NN    As above, but uses specified port number rather
    #            than the http_port number. Implies accel.
    #
    #       protocol=    Protocol to reconstruct accelerated requests with.
    #            Defaults to http.
    #
    #       disable-pmtu-discovery=
    #            Control Path-MTU discovery usage:
    #                off        lets OS decide on what to do (default).
    #                transparent    disable PMTU discovery when transparent
    #                    support is enabled.
    #                always    disable always PMTU discovery.
    #
    #            In many setups of transparently intercepting proxies
    #            Path-MTU discovery can not work on traffic towards the
    #            clients. This is the case when the intercepting device
    #            does not fully track connections and fails to forward
    #            ICMP must fragment messages to the cache server. If you
    #            have such setup and experience that certain clients
    #            sporadically hang or never complete requests set
    #            disable-pmtu-discovery option to 'transparent'.
    #
    #       name=    Specifies a internal name for the port. Defaults to
    #            the port specification (port or addr:port)
    #
    #    If you run Squid on a dual-homed machine with an internal
    #    and an external interface we recommend you to specify the
    #    internal address:port in http_port. This way Squid will only be
    #    visible on the internal address.
    #
    # Squid normally listens to port 3128
    http_port 3128

    #  TAG: https_port
    #    Usage:  [ip:]port cert=certificate.pem [key=key.pem] [options...]
    #
    #    The socket address where Squid will listen for HTTPS client
    #    requests.
    #
    #    This is really only useful for situations where you are running
    #    squid in accelerator mode and you want to do the SSL work at the
    #    accelerator level.
    #
    #    You may specify multiple socket addresses on multiple lines,
    #    each with their own SSL certificate and/or options.
    #
    #    Options:
    #
    #       accel    Accelerator mode. Also needs at least one of
    #            defaultsite or vhost.
    #
    #       defaultsite=    The name of the https site presented on
    #               this port. Implies accel.
    #
    #       vhost    Accelerator mode using Host header for virtual
    #            domain support. Requires a wildcard certificate
    #            or other certificate valid for more than one domain.
    #            Implies accel.
    #
    #       protocol=    Protocol to reconstruct accelerated requests with.
    #            Defaults to https.
    #
    #       cert=    Path to SSL certificate (PEM format).
    #
    #       key=        Path to SSL private key file (PEM format)
    #            if not specified, the certificate file is
    #            assumed to be a combined certificate and
    #            key file.
    #
    #       version=    The version of SSL/TLS supported
    #                1    automatic (default)
    #                2    SSLv2 only
    #                3    SSLv3 only
    #                4    TLSv1 only
    #
    #       cipher=    Colon separated list of supported ciphers.
    #
    #       options=    Various SSL engine options. The most important
    #            being:
    #                NO_SSLv2  Disallow the use of SSLv2
    #                NO_SSLv3  Disallow the use of SSLv3
    #                NO_TLSv1  Disallow the use of TLSv1
    #                SINGLE_DH_USE Always create a new key when using
    #                      temporary/ephemeral DH key exchanges
    #            See src/ssl_support.c or OpenSSL SSL_CTX_set_options
    #            documentation for a complete list of options.
    #
    #       clientca=    File containing the list of CAs to use when
    #            requesting a client certificate.
    #
    #       cafile=    File containing additional CA certificates to
    #            use when verifying client certificates. If unset
    #            clientca will be used.
    #
    #       capath=    Directory containing additional CA certificates
    #            and CRL lists to use when verifying client certificates.
    #
    #       crlfile=    File of additional CRL lists to use when verifying
    #            the client certificate, in addition to CRLs stored in
    #            the capath. Implies VERIFY_CRL flag below.
    #
    #       dhparams=    File containing DH parameters for temporary/ephemeral
    #            DH key exchanges.
    #
    #       sslflags=    Various flags modifying the use of SSL:
    #                DELAYED_AUTH
    #                Don't request client certificates
    #                immediately, but wait until acl processing
    #                requires a certificate (not yet implemented).
    #                NO_DEFAULT_CA
    #                Don't use the default CA lists built in
    #                to OpenSSL.
    #                NO_SESSION_REUSE
    #                Don't allow for session reuse. Each connection
    #                will result in a new SSL session.
    #                VERIFY_CRL
    #                Verify CRL lists when accepting client
    #                certificates.
    #                VERIFY_CRL_ALL
    #                Verify CRL lists for all certificates in the
    #                client certificate chain.
    #
    #       sslcontext=    SSL session ID context identifier.
    #
    #       vport    Accelerator with IP based virtual host support.
    #
    #       vport=NN    As above, but uses specified port number rather
    #            than the https_port number. Implies accel.
    #
    #       name=    Specifies a internal name for the port. Defaults to
    #            the port specification (port or addr:port)
    #
    #
    #Default:
    # none

    #  TAG: tcp_outgoing_tos
    #    Allows you to select a TOS/Diffserv value to mark outgoing
    #    connections with, based on the username or source address
    #    making the request.
    #
    #    tcp_outgoing_tos ds-field [!]aclname ...
    #
    #    Example where normal_service_net uses the TOS value 0x00
    #    and good_service_net uses 0x20
    #
    #    acl normal_service_net src 10.0.0.0/255.255.255.0
    #    acl good_service_net src 10.0.1.0/255.255.255.0
    #    tcp_outgoing_tos 0x00 normal_service_net
    #    tcp_outgoing_tos 0x20 good_service_net
    #
    #    TOS/DSCP values really only have local significance - so you should
    #    know what you're specifying. For more information, see RFC2474 and
    #    RFC3260.
    #
    #    The TOS/DSCP byte must be exactly that - a octet value  0 - 255, or
    #    "default" to use whatever default your host has. Note that in
    #    practice often only values 0 - 63 is usable as the two highest bits
    #    have been redefined for use by ECN (RFC3168).
    #
    #    Processing proceeds in the order specified, and stops at first fully
    #    matching line.
    #
    #    Note: The use of this directive using client dependent ACLs is
    #    incompatible with the use of server side persistent connections. To
    #    ensure correct results it is best to set server_persisten_connections
    #    to off when using this directive in such configurations.
    #
    #Default:
    # none

    #  TAG: clientside_tos
    #    Allows you to select a TOS/Diffserv value to mark client-side
    #    connections with, based on the username or source address
    #    making the request.
    #
    #Default:
    # none

    #  TAG: tcp_outgoing_address
    #    Allows you to map requests to different outgoing IP addresses
    #    based on the username or source address of the user making
    #    the request.
    #
    #    tcp_outgoing_address ipaddr [[!]aclname] ...
    #
    #    Example where requests from 10.0.0.0/24 will be forwarded
    #    with source address 10.1.0.1, 10.0.2.0/24 forwarded with
    #    source address 10.1.0.2 and the rest will be forwarded with
    #    source address 10.1.0.3.
    #
    #    acl normal_service_net src 10.0.0.0/24
    #    acl good_service_net src 10.0.2.0/24
    #    tcp_outgoing_address 10.1.0.1 normal_service_net
    #    tcp_outgoing_address 10.1.0.2 good_service_net
    #    tcp_outgoing_address 10.1.0.3
    #
    #    Processing proceeds in the order specified, and stops at first fully
    #    matching line.
    #
    #    Note: The use of this directive using client dependent ACLs is
    #    incompatible with the use of server side persistent connections. To
    #    ensure correct results it is best to set server_persistent_connections
    #    to off when using this directive in such configurations.
    #
    #Default:
    # none


    # SSL OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: ssl_unclean_shutdown
    #    Some browsers (especially MSIE) bugs out on SSL shutdown
    #    messages.
    #
    #Default:
    # ssl_unclean_shutdown off

    #  TAG: ssl_engine
    #    The OpenSSL engine to use. You will need to set this if you
    #    would like to use hardware SSL acceleration for example.
    #
    #Default:
    # none

    #  TAG: sslproxy_client_certificate
    #    Client SSL Certificate to use when proxying https:// URLs
    #
    #Default:
    # none

    #  TAG: sslproxy_client_key
    #    Client SSL Key to use when proxying https:// URLs
    #
    #Default:
    # none

    #  TAG: sslproxy_version
    #    SSL version level to use when proxying https:// URLs
    #
    #Default:
    # sslproxy_version 1

    #  TAG: sslproxy_options
    #    SSL engine options to use when proxying https:// URLs
    #
    #Default:
    # none

    #  TAG: sslproxy_cipher
    #    SSL cipher list to use when proxying https:// URLs
    #
    #Default:
    # none

    #  TAG: sslproxy_cafile
    #    file containing CA certificates to use when verifying server
    #    certificates while proxying https:// URLs
    #
    #Default:
    # none

    #  TAG: sslproxy_capath
    #    directory containing CA certificates to use when verifying
    #    server certificates while proxying https:// URLs
    #
    #Default:
    # none

    #  TAG: sslproxy_flags
    #    Various flags modifying the use of SSL while proxying https:// URLs:
    #        DONT_VERIFY_PEER    Accept certificates even if they fail to
    #                verify.
    #        NO_DEFAULT_CA    Don't use the default CA list built in
    #                to OpenSSL.
    #
    #Default:
    # none

    #  TAG: sslpassword_program
    #    Specify a program used for entering SSL key passphrases
    #    when using encrypted SSL certificate keys. If not specified
    #    keys must either be unencrypted, or Squid started with the -N
    #    option to allow it to query interactively for the passphrase.
    #
    #Default:
    # none


    # OPTIONS WHICH AFFECT THE NEIGHBOR SELECTION ALGORITHM
    # -----------------------------------------------------------------------------

    #  TAG: cache_peer
    #    To specify other caches in a hierarchy, use the format:
    #
    #        cache_peer hostname type http-port icp-port [options]
    #
    #    For example,
    #
    #    #                                        proxy  icp
    #    #          hostname             type     port   port  options
    #    #          -------------------- -------- ----- -----  -----------
    #    cache_peer parent.foo.net       parent    3128  3130  proxy-only default
    #    cache_peer sib1.foo.net         sibling   3128  3130  proxy-only
    #    cache_peer sib2.foo.net         sibling   3128  3130  proxy-only
    #
    #          type:  either 'parent', 'sibling', or 'multicast'.
    #
    #    proxy-port:  The port number where the cache listens for proxy
    #             requests.
    #
    #      icp-port:  Used for querying neighbor caches about
    #             objects.  To have a non-ICP neighbor
    #             specify '7' for the ICP port and make sure the
    #             neighbor machine has the UDP echo port
    #             enabled in its /etc/inetd.conf file.
    #        NOTE: Also requires icp_port option enabled to send/receive
    #              requests via this method.
    #
    #        options: proxy-only
    #             weight=n
    #             basetime=n
    #             ttl=n
    #             no-query
    #             background-ping
    #             default
    #             round-robin
    #             weighted-round-robin
    #             carp
    #             userhash
    #             sourcehash
    #             multicast-responder
    #             closest-only
    #             no-digest
    #             no-netdb-exchange
    #             no-delay
    #             login=user:password | PASS | *:password
    #             connect-timeout=nn
    #             digest-url=url
    #             allow-miss
    #             max-conn=n
    #             htcp
    #             htcp-oldsquid
    #             originserver
    #             name=xxx
    #             forceddomain=name
    #             ssl
    #             sslcert=/path/to/ssl/certificate
    #             sslkey=/path/to/ssl/key
    #             sslversion=1|2|3|4
    #             sslcipher=...
    #             ssloptions=...
    #             front-end-https[=on|auto]
    #
    #             use 'proxy-only' to specify objects fetched
    #             from this cache should not be saved locally.
    #
    #             use 'weight=n' to affect the selection of a peer
    #             during any weighted peer-selection mechanisms.
    #             The weight must be an integer; default is 1,
    #             larger weights are favored more.
    #             This option does not affect parent selection if a peering
    #             protocol is not in use.
    #
    #             use 'basetime=n' to specify a base amount to
    #             be subtracted from round trip times of parents.
    #             It is subtracted before division by weight in calculating
    #             which parent to fectch from. If the rtt is less than the
    #             base time the rtt is set to a minimal value.
    #
    #             use 'ttl=n' to specify a IP multicast TTL to use
    #             when sending an ICP queries to this address.
    #             Only useful when sending to a multicast group.
    #             Because we don't accept ICP replies from random
    #             hosts, you must configure other group members as
    #             peers with the 'multicast-responder' option below.
    #
    #             use 'no-query' to NOT send ICP queries to this
    #             neighbor.
    #
    #             use 'background-ping' to only send ICP queries to this
    #             neighbor infrequently. This is used to keep the neighbor
    #             round trip time updated and is usually used in
    #             conjunction with weighted-round-robin.
    #
    #             use 'default' if this is a parent cache which can
    #             be used as a "last-resort" if a peer cannot be located
    #             by any of the peer-selection mechanisms.
    #             If specified more than once, only the first is used.
    #
    #             use 'round-robin' to define a set of parents which
    #             should be used in a round-robin fashion in the
    #             absence of any ICP queries.
    #
    #             use 'weighted-round-robin' to define a set of parents
    #             which should be used in a round-robin fashion with the
    #             frequency of each parent being based on the round trip
    #             time. Closer parents are used more often.
    #             Usually used for background-ping parents.
    #
    #             use 'carp' to define a set of parents which should
    #             be used as a CARP array. The requests will be
    #             distributed among the parents based on the CARP load
    #             balancing hash function based on their weight.
    #
    #             use 'userhash' to load-balance amongst a set of parents
    #             based on the client proxy_auth or ident username.
    #
    #             use 'sourcehash' to load-balance amongst a set of parents
    #             based on the client source ip.
    #
    #             'multicast-responder' indicates the named peer
    #             is a member of a multicast group.  ICP queries will
    #             not be sent directly to the peer, but ICP replies
    #             will be accepted from it.
    #
    #             'closest-only' indicates that, for ICP_OP_MISS
    #             replies, we'll only forward CLOSEST_PARENT_MISSes
    #             and never FIRST_PARENT_MISSes.
    #
    #             use 'no-digest' to NOT request cache digests from
    #             this neighbor.
    #
    #             'no-netdb-exchange' disables requesting ICMP
    #             RTT database (NetDB) from the neighbor.
    #
    #             use 'no-delay' to prevent access to this neighbor
    #             from influencing the delay pools.
    #
    #             use 'login=user:password' if this is a personal/workgroup
    #             proxy and your parent requires proxy authentication.
    #             Note: The string can include URL escapes (i.e. %20 for
    #             spaces). This also means % must be written as %%.
    #
    #             use 'login=PASS' if users must authenticate against
    #             the upstream proxy or in the case of a reverse proxy
    #             configuration, the origin web server.  This will pass
    #             the users credentials as they are to the peer.
    #             This only works for the Basic HTTP authentication scheme.
    #             Note: To combine this with proxy_auth both proxies must
    #             share the same user database as HTTP only allows for
    #             a single login (one for proxy, one for origin server).
    #             Also be warned this will expose your users proxy
    #             password to the peer. USE WITH CAUTION
    #
    #             use 'login=*:password' to pass the username to the
    #             upstream cache, but with a fixed password. This is meant
    #             to be used when the peer is in another administrative
    #             domain, but it is still needed to identify each user.
    #             The star can optionally be followed by some extra
    #             information which is added to the username. This can
    #             be used to identify this proxy to the peer, similar to
    #             the login=username:password option above.
    #
    #             use 'connect-timeout=nn' to specify a peer
    #             specific connect timeout (also see the
    #             peer_connect_timeout directive)
    #
    #             use 'digest-url=url' to tell Squid to fetch the cache
    #             digest (if digests are enabled) for this host from
    #             the specified URL rather than the Squid default
    #             location.
    #
    #             use 'allow-miss' to disable Squid's use of only-if-cached
    #             when forwarding requests to siblings. This is primarily
    #             useful when icp_hit_stale is used by the sibling. To
    #             extensive use of this option may result in forwarding
    #             loops, and you should avoid having two-way peerings
    #             with this option. (for example to deny peer usage on
    #             requests from peer by denying cache_peer_access if the
    #             source is a peer)
    #
    #             use 'max-conn=n' to limit the amount of connections Squid
    #             may open to this peer.
    #
    #             use 'htcp' to send HTCP, instead of ICP, queries
    #             to the neighbor.  You probably also want to
    #             set the "icp port" to 4827 instead of 3130.
    #             You MUST also set htcp_access expicitly. The default of
    #             deny all will prevent peer traffic.
    #
    #             use 'htcp-oldsquid' to send HTCP to old Squid versions
    #             You MUST also set htcp_access expicitly. The default of
    #             deny all will prevent peer traffic.            
    #
    #             'originserver' causes this parent peer to be contacted as
    #             a origin server. Meant to be used in accelerator setups.
    #
    #             use 'name=xxx' if you have multiple peers on the same
    #             host but different ports. This name can be used to
    #             differentiate the peers in cache_peer_access and similar
    #             directives.
    #
    #             use 'forceddomain=name' to forcibly set the Host header
    #             of requests forwarded to this peer. Useful in accelerator
    #             setups where the server (peer) expects a certain domain
    #             name and using redirectors to feed this domain name
    #             is not feasible.
    #
    #             use 'ssl' to indicate connections to this peer should
    #             be SSL/TLS encrypted.
    #
    #             use 'sslcert=/path/to/ssl/certificate' to specify a client
    #             SSL certificate to use when connecting to this peer.
    #
    #             use 'sslkey=/path/to/ssl/key' to specify the private SSL
    #             key corresponding to sslcert above. If 'sslkey' is not
    #             specified 'sslcert' is assumed to reference a
    #             combined file containing both the certificate and the key.
    #
    #             use sslversion=1|2|3|4 to specify the SSL version to use
    #             when connecting to this peer
    #            1 = automatic (default)
    #            2 = SSL v2 only
    #            3 = SSL v3 only
    #            4 = TLS v1 only
    #
    #             use sslcipher=... to specify the list of valid SSL ciphers
    #             to use when connecting to this peer.
    #
    #             use ssloptions=... to specify various SSL engine options:
    #            NO_SSLv2  Disallow the use of SSLv2
    #            NO_SSLv3  Disallow the use of SSLv3
    #            NO_TLSv1  Disallow the use of TLSv1
    #             See src/ssl_support.c or the OpenSSL documentation for
    #             a more complete list.
    #
    #             use sslcafile=... to specify a file containing
    #             additional CA certificates to use when verifying the
    #             peer certificate.
    #
    #             use sslcapath=... to specify a directory containing
    #             additional CA certificates to use when verifying the
    #             peer certificate.
    #
    #             use sslcrlfile=... to specify a certificate revocation
    #             list file to use when verifying the peer certificate.
    #            
    #             use sslflags=... to specify various flags modifying the
    #             SSL implementation:
    #            DONT_VERIFY_PEER
    #                Accept certificates even if they fail to
    #                verify.
    #            NO_DEFAULT_CA
    #                Don't use the default CA list built in
    #                to OpenSSL.
    #            DONT_VERIFY_DOMAIN
    #                Don't verify the peer certificate
    #                matches the server name
    #
    #             use ssldomain= to specify the peer name as advertised
    #             in it's certificate. Used for verifying the correctness
    #             of the received peer certificate. If not specified the
    #             peer hostname will be used.
    #
    #             use front-end-https to enable the "Front-End-Https: On"
    #             header needed when using Squid as a SSL frontend in front
    #             of Microsoft OWA. See MS KB document Q307347 for details
    #             on this header. If set to auto the header will
    #             only be added if the request is forwarded as a https://

    #             URL.
    #
    #Default:
    # none

    #  TAG: cache_peer_domain
    #    Use to limit the domains for which a neighbor cache will be
    #    queried.  Usage:
    #
    #    cache_peer_domain cache-host domain [domain ...]
    #    cache_peer_domain cache-host !domain
    #
    #    For example, specifying
    #
    #        cache_peer_domain parent.foo.net    .edu
    #
    #    has the effect such that UDP query packets are sent to
    #    'bigserver' only when the requested object exists on a
    #    server in the .edu domain.  Prefixing the domainname
    #    with '!' means the cache will be queried for objects
    #    NOT in that domain.
    #
    #    NOTE:    * Any number of domains may be given for a cache-host,
    #          either on the same or separate lines.
    #        * When multiple domains are given for a particular
    #          cache-host, the first matched domain is applied.
    #        * Cache hosts with no domain restrictions are queried
    #          for all requests.
    #        * There are no defaults.
    #        * There is also a 'cache_peer_access' tag in the ACL
    #          section.
    #
    #Default:
    # none

    #  TAG: cache_peer_access
    #    Similar to 'cache_peer_domain' but provides more flexibility by
    #    using ACL elements.
    #
    #    cache_peer_access cache-host allow|deny [!]aclname ...
    #
    #    The syntax is identical to 'http_access' and the other lists of
    #    ACL elements.  See the comments for 'http_access' below, or
    #    the Squid FAQ (http://wiki.squid-cache.org/SquidFaq/SquidAcl).
    #
    #Default:
    # none

    #  TAG: neighbor_type_domain
    #    usage: neighbor_type_domain neighbor parent|sibling domain domain ...
    #
    #    Modifying the neighbor type for specific domains is now
    #    possible.  You can treat some domains differently than the the
    #    default neighbor type specified on the 'cache_peer' line.
    #    Normally it should only be necessary to list domains which
    #    should be treated differently because the default neighbor type
    #    applies for hostnames which do not match domains listed here.
    #
    #EXAMPLE:
    #    cache_peer cache.foo.org parent 3128 3130
    #    neighbor_type_domain cache.foo.org sibling .com .net
    #    neighbor_type_domain cache.foo.org sibling .au .de
    #
    #Default:
    # none

    #  TAG: dead_peer_timeout    (seconds)
    #    This controls how long Squid waits to declare a peer cache
    #    as "dead."  If there are no ICP replies received in this
    #    amount of time, Squid will declare the peer dead and not
    #    expect to receive any further ICP replies.  However, it
    #    continues to send ICP queries, and will mark the peer as
    #    alive upon receipt of the first subsequent ICP reply.
    #
    #    This timeout also affects when Squid expects to receive ICP
    #    replies from peers.  If more than 'dead_peer' seconds have
    #    passed since the last ICP reply was received, Squid will not
    #    expect to receive an ICP reply on the next query.  Thus, if
    #    your time between requests is greater than this timeout, you
    #    will see a lot of requests sent DIRECT to origin servers
    #    instead of to your parents.
    #
    #Default:
    # dead_peer_timeout 10 seconds

    #  TAG: hierarchy_stoplist
    #    A list of words which, if found in a URL, cause the object to
    #    be handled directly by this cache.  In other words, use this
    #    to not query neighbor caches for certain objects.  You may
    #    list this option multiple times.
    #    Note: never_direct overrides this option.
    #We recommend you to use at least the following line.
    hierarchy_stoplist cgi-bin ?


    # MEMORY CACHE OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: cache_mem    (bytes)
    #    NOTE: THIS PARAMETER DOES NOT SPECIFY THE MAXIMUM PROCESS SIZE.
    #    IT ONLY PLACES A LIMIT ON HOW MUCH ADDITIONAL MEMORY SQUID WILL
    #    USE AS A MEMORY CACHE OF OBJECTS. SQUID USES MEMORY FOR OTHER
    #    THINGS AS WELL. SEE THE SQUID FAQ SECTION 8 FOR DETAILS.
    #
    #    'cache_mem' specifies the ideal amount of memory to be used
    #    for:
    #        * In-Transit objects
    #        * Hot Objects
    #        * Negative-Cached objects
    #
    #    Data for these objects are stored in 4 KB blocks.  This
    #    parameter specifies the ideal upper limit on the total size of
    #    4 KB blocks allocated.  In-Transit objects take the highest
    #    priority.
    #
    #    In-transit objects have priority over the others.  When
    #    additional space is needed for incoming data, negative-cached
    #    and hot objects will be released.  In other words, the
    #    negative-cached and hot objects will fill up any unused space
    #    not needed for in-transit objects.
    #
    #    If circumstances require, this limit will be exceeded.
    #    Specifically, if your incoming request rate requires more than
    #    'cache_mem' of memory to hold in-transit objects, Squid will
    #    exceed this limit to satisfy the new requests.  When the load
    #    decreases, blocks will be freed until the high-water mark is
    #    reached.  Thereafter, blocks will be used to store hot
    #    objects.
    #
    #Default:
    # cache_mem 8 MB

    #  TAG: maximum_object_size_in_memory    (bytes)
    #    Objects greater than this size will not be attempted to kept in
    #    the memory cache. This should be set high enough to keep objects
    #    accessed frequently in memory to improve performance whilst low
    #    enough to keep larger objects from hoarding cache_mem.
    #
    #Default:
    # maximum_object_size_in_memory 8 KB

    #  TAG: memory_replacement_policy
    #    The memory replacement policy parameter determines which
    #    objects are purged from memory when memory space is needed.
    #
    #    See cache_replacement_policy for details.
    #
    #Default:
    # memory_replacement_policy lru


    # DISK CACHE OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: cache_replacement_policy
    #    The cache replacement policy parameter determines which
    #    objects are evicted (replaced) when disk space is needed.
    #
    #        lru       : Squid's original list based LRU policy
    #        heap GDSF : Greedy-Dual Size Frequency
    #        heap LFUDA: Least Frequently Used with Dynamic Aging
    #        heap LRU  : LRU policy implemented using a heap
    #
    #    Applies to any cache_dir lines listed below this.
    #
    #    The LRU policies keeps recently referenced objects.
    #
    #    The heap GDSF policy optimizes object hit rate by keeping smaller
    #    popular objects in cache so it has a better chance of getting a
    #    hit.  It achieves a lower byte hit rate than LFUDA though since
    #    it evicts larger (possibly popular) objects.
    #
    #    The heap LFUDA policy keeps popular objects in cache regardless of
    #    their size and thus optimizes byte hit rate at the expense of
    #    hit rate since one large, popular object will prevent many
    #    smaller, slightly less popular objects from being cached.
    #
    #    Both policies utilize a dynamic aging mechanism that prevents
    #    cache pollution that can otherwise occur with frequency-based
    #    replacement policies.
    #
    #    NOTE: if using the LFUDA replacement policy you should increase
    #    the value of maximum_object_size above its default of 4096 KB to
    #    to maximize the potential byte hit rate improvement of LFUDA.
    #
    #    For more information about the GDSF and LFUDA cache replacement
    #    policies see http://www.hpl.hp.com/techreports/1999/HPL-1999-69.html
    #    and http://fog.hpl.external.hp.com/techreports/98/HPL-98-173.html.
    #
    #Default:
    # cache_replacement_policy lru

    #  TAG: cache_dir
    #    Usage:
    #
    #    cache_dir Type Directory-Name Fs-specific-data [options]
    #
    #    You can specify multiple cache_dir lines to spread the
    #    cache among different disk partitions.
    #
    #    Type specifies the kind of storage system to use. Only "ufs"
    #    is built by default. To enable any of the other storage systems
    #    see the --enable-storeio configure option.
    #
    #    'Directory' is a top-level directory where cache swap
    #    files will be stored.  If you want to use an entire disk
    #    for caching, this can be the mount-point directory.
    #    The directory must exist and be writable by the Squid
    #    process.  Squid will NOT create this directory for you.
    #
    #    The ufs store type:
    #
    #    "ufs" is the old well-known Squid storage format that has always
    #    been there.
    #
    #    cache_dir ufs Directory-Name Mbytes L1 L2 [options]
    #
    #    'Mbytes' is the amount of disk space (MB) to use under this
    #    directory.  The default is 100 MB.  Change this to suit your
    #    configuration.  Do NOT put the size of your disk drive here.
    #    Instead, if you want Squid to use the entire disk drive,
    #    subtract 20% and use that value.
    #
    #    'Level-1' is the number of first-level subdirectories which
    #    will be created under the 'Directory'.  The default is 16.
    #
    #    'Level-2' is the number of second-level subdirectories which
    #    will be created under each first-level directory.  The default
    #    is 256.
    #
    #    The aufs store type:
    #
    #    "aufs" uses the same storage format as "ufs", utilizing
    #    POSIX-threads to avoid blocking the main Squid process on
    #    disk-I/O. This was formerly known in Squid as async-io.
    #
    #    cache_dir aufs Directory-Name Mbytes L1 L2 [options]
    #
    #    see argument descriptions under ufs above
    #
    #    The diskd store type:
    #
    #    "diskd" uses the same storage format as "ufs", utilizing a
    #    separate process to avoid blocking the main Squid process on
    #    disk-I/O.
    #
    #    cache_dir diskd Directory-Name Mbytes L1 L2 [options] [Q1=n] [Q2=n]
    #
    #    see argument descriptions under ufs above
    #
    #    Q1 specifies the number of unacknowledged I/O requests when Squid
    #    stops opening new files. If this many messages are in the queues,
    #    Squid won't open new files. Default is 64
    #
    #    Q2 specifies the number of unacknowledged messages when Squid
    #    starts blocking.  If this many messages are in the queues,
    #    Squid blocks until it receives some replies. Default is 72
    #
    #    When Q1 < Q2 (the default), the cache directory is optimized
    #    for lower response time at the expense of a decrease in hit
    #    ratio.  If Q1 > Q2, the cache directory is optimized for
    #    higher hit ratio at the expense of an increase in response
    #    time.
    #
    #    The coss store type:
    #
    #    NP: COSS filesystem in 3.0 has been deemed too unstable for
    #        production use and has thus been removed from this 3.0
    #        STABLE release. We hope that it can be made usable again
    #        in a future release.
    #
    #    block-size=n defines the "block size" for COSS cache_dir's.
    #    Squid uses file numbers as block numbers.  Since file numbers
    #    are limited to 24 bits, the block size determines the maximum
    #    size of the COSS partition.  The default is 512 bytes, which
    #    leads to a maximum cache_dir size of 512<<24, or 8 GB.  Note
    #    you should not change the coss block size after Squid
    #    has written some objects to the cache_dir.
    #
    #    The coss file store has changed from 2.5. Now it uses a file
    #    called 'stripe' in the directory names in the config - and
    #    this will be created by squid -z.
    #
    #    The null store type:
    #
    #    no options are allowed or required
    #
    #    Common options:
    #
    #    no-store, no new objects should be stored to this cache_dir
    #
    #    max-size=n, refers to the max object size this storedir supports.
    #    It is used to initially choose the storedir to dump the object.
    #    Note: To make optimal use of the max-size limits you should order
    #    the cache_dir lines with the smallest max-size value first and the
    #    ones with no max-size specification last.
    #
    #    Note for coss, max-size must be less than COSS_MEMBUF_SZ,
    #    which can be changed with the --with-coss-membuf-size=N configure
    #    option.
    #
    #Default:
    # cache_dir ufs /usr/local/squid3.0/var/cache 100 16 256

    #  TAG: store_dir_select_algorithm
    #    Set this to 'round-robin' as an alternative.
    #
    #Default:
    # store_dir_select_algorithm least-load

    #  TAG: max_open_disk_fds
    #    To avoid having disk as the I/O bottleneck Squid can optionally
    #    bypass the on-disk cache if more than this amount of disk file
    #    descriptors are open.
    #
    #    A value of 0 indicates no limit.
    #
    #Default:
    # max_open_disk_fds 0

    #  TAG: minimum_object_size    (bytes)
    #    Objects smaller than this size will NOT be saved on disk.  The
    #    value is specified in kilobytes, and the default is 0 KB, which
    #    means there is no minimum.
    #
    #Default:
    # minimum_object_size 0 KB

    #  TAG: maximum_object_size    (bytes)
    #    Objects larger than this size will NOT be saved on disk.  The
    #    value is specified in kilobytes, and the default is 4MB.  If
    #    you wish to get a high BYTES hit ratio, you should probably
    #    increase this (one 32 MB object hit counts for 3200 10KB
    #    hits).  If you wish to increase speed more than your want to
    #    save bandwidth you should leave this low.
    #
    #    NOTE: if using the LFUDA replacement policy you should increase
    #    this value to maximize the byte hit rate improvement of LFUDA!
    #    See replacement_policy below for a discussion of this policy.
    #
    #Default:
    # maximum_object_size 4096 KB

    #  TAG: cache_swap_low    (percent, 0-100)
    #  TAG: cache_swap_high    (percent, 0-100)
    #
    #    The low- and high-water marks for cache object replacement.
    #    Replacement begins when the swap (disk) usage is above the
    #    low-water mark and attempts to maintain utilization near the
    #    low-water mark.  As swap utilization gets close to high-water
    #    mark object eviction becomes more aggressive.  If utilization is
    #    close to the low-water mark less replacement is done each time.
    #
    #    Defaults are 90% and 95%. If you have a large cache, 5% could be
    #    hundreds of MB. If this is the case you may wish to set these
    #    numbers closer together.
    #
    #Default:
    # cache_swap_low 90
    # cache_swap_high 95


    # LOGFILE OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: logformat
    #    Usage:
    #
    #    logformat <name> <format specification>
    #
    #    Defines an access log format.
    #
    #    The <format specification> is a string with embedded % format codes
    #
    #    % format codes all follow the same basic structure where all but
    #    the formatcode is optional. Output strings are automatically escaped
    #    as required according to their context and the output format
    #    modifiers are usually not needed, but can be specified if an explicit
    #    output format is desired.
    #
    #        % ["|[|'|#] [-] [[0]width] [{argument}] formatcode
    #
    #        "    output in quoted string format
    #        [    output in squid text log format as used by log_mime_hdrs
    #        #    output in URL quoted format
    #        '    output as-is
    #
    #        -    left aligned
    #        width    field width. If starting with 0 the
    #            output is zero padded
    #        {arg}    argument such as header name etc
    #
    #    Format codes:
    #
    #        >a    Client source IP address
    #        >A    Client FQDN
    #        >p    Client source port
    #        <A    Server IP address or peer name
    #        la    Local IP address (http_port)
    #        lp    Local port number (http_port)
    #        ts    Seconds since epoch
    #        tu    subsecond time (milliseconds)
    #        tl    Local time. Optional strftime format argument
    #            default %d/%b/%Y:%H:%M:%S %z
    #        tg    GMT time. Optional strftime format argument
    #            default %d/%b/%Y:%H:%M:%S %z
    #        tr    Response time (milliseconds)
    #        >h    Request header. Optional header name argument
    #            on the format header[:[separator]element]
    #        <h    Reply header. Optional header name argument
    #            as for >h
    #        un    User name
    #        ul    User name from authentication
    #        ui    User name from ident
    #        us    User name from SSL
    #        ue    User name from external acl helper
    #        Hs    HTTP status code
    #        Ss    Squid request status (TCP_MISS etc)
    #        Sh    Squid hierarchy status (DEFAULT_PARENT etc)
    #        mt    MIME content type
    #        rm    Request method (GET/POST etc)
    #        ru    Request URL
    #        rp    Request URL-Path excluding hostname
    #        rv    Request protocol version
    #        et    Tag returned by external acl
    #        ea    Log string returned by external acl
    #        <st    Reply size including HTTP headers
    #        >st    Request size including HTTP headers
    #        st    Request+Reply size including HTTP headers
    #        <sH    Reply high offset sent
    #        <sS    Upstream object size
    #        %    a literal % character
    #
    #    The default formats available (which do not need re-defining) are:
    #
    #logformat squid %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt
    #logformat squidmime %ts.%03tu %6tr %>a %Ss/%03Hs %<st %rm %ru %un %Sh/%<A %mt [%>h] [%<h]
    #logformat common %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st %Ss:%Sh
    #logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
    #
    #Default:
    # none

    #  TAG: access_log
    #    These files log client request activities. Has a line every HTTP or
    #    ICP request. The format is:
    #    access_log <filepath> [<logformat name> [acl acl ...]]
    #    access_log none [acl acl ...]]
    #
    #    Will log to the specified file using the specified format (which
    #    must be defined in a logformat directive) those entries which match
    #    ALL the acl's specified (which must be defined in acl clauses).
    #    If no acl is specified, all requests will be logged to this file.
    #
    #    To disable logging of a request use the filepath "none", in which case
    #    a logformat name should not be specified.
    #
    #    To log the request via syslog specify a filepath of "syslog":
    #
    #    access_log syslog[:facility.priority] [format [acl1 [acl2 ....]]]
    #    where facility could be any of:
    #    authpriv, daemon, local0 .. local7 or user.
    #
    #    And priority could be any of:
    #    err, warning, notice, info, debug.
    access_log /usr/local/squid3.0/var/logs/access.log squid

    #  TAG: log_access    allow|deny acl acl...
    #    This options allows you to control which requests gets logged
    #    to access.log (see access_log directive). Requests denied for
    #    logging will also not be accounted for in performance counters.
    #
    #Default:
    # none

    #  TAG: cache_log
    #    Cache logging file. This is where general information about
    #    your cache's behavior goes. You can increase the amount of data
    #    logged to this file with the "debug_options" tag below.
    #
    #Default:
    # cache_log /usr/local/squid3.0/var/logs/cache.log

    #  TAG: cache_store_log
    #    Logs the activities of the storage manager.  Shows which
    #    objects are ejected from the cache, and which objects are
    #    saved and for how long.  To disable, enter "none". There are
    #    not really utilities to analyze this data, so you can safely
    #    disable it.
    #
    #Default:
    # cache_store_log /usr/local/squid3.0/var/logs/store.log

    #  TAG: cache_swap_state
    #    Location for the cache "swap.state" file. This index file holds
    #    the metadata of objects saved on disk.  It is used to rebuild
    #    the cache during startup.  Normally this file resides in each
    #    'cache_dir' directory, but you may specify an alternate
    #    pathname here.  Note you must give a full filename, not just
    #    a directory. Since this is the index for the whole object
    #    list you CANNOT periodically rotate it!
    #
    #    If %s can be used in the file name it will be replaced with a
    #    a representation of the cache_dir name where each / is replaced
    #    with '.'. This is needed to allow adding/removing cache_dir
    #    lines when cache_swap_log is being used.
    #
    #    If have more than one 'cache_dir', and %s is not used in the name
    #    these swap logs will have names such as:
    #
    #        cache_swap_log.00
    #        cache_swap_log.01
    #        cache_swap_log.02
    #
    #    The numbered extension (which is added automatically)
    #    corresponds to the order of the 'cache_dir' lines in this
    #    configuration file.  If you change the order of the 'cache_dir'
    #    lines in this file, these index files will NOT correspond to
    #    the correct 'cache_dir' entry (unless you manually rename
    #    them).  We recommend you do NOT use this option.  It is
    #    better to keep these index files in each 'cache_dir' directory.
    #
    #Default:
    # none

    #  TAG: logfile_rotate
    #    Specifies the number of logfile rotations to make when you
    #    type 'squid -k rotate'. The default is 10, which will rotate
    #    with extensions 0 through 9. Setting logfile_rotate to 0 will
    #    disable the file name rotation, but the logfiles are still closed
    #    and re-opened. This will enable you to rename the logfiles
    #    yourself just before sending the rotate signal.
    #
    #    Note, the 'squid -k rotate' command normally sends a USR1
    #    signal to the running squid process.  In certain situations
    #    (e.g. on Linux with Async I/O), USR1 is used for other
    #    purposes, so -k rotate uses another signal.  It is best to get
    #    in the habit of using 'squid -k rotate' instead of 'kill -USR1
    #    <pid>'.
    #
    #Default:
    # logfile_rotate 10

    #  TAG: emulate_httpd_log    on|off
    #    The Cache can emulate the log file format which many 'httpd'
    #    programs use.  To disable/enable this emulation, set
    #    emulate_httpd_log to 'off' or 'on'.  The default
    #    is to use the native log format since it includes useful
    #    information Squid-specific log analyzers use.
    #
    #Default:
    # emulate_httpd_log off

    #  TAG: log_ip_on_direct    on|off
    #    Log the destination IP address in the hierarchy log tag when going
    #    direct. Earlier Squid versions logged the hostname here. If you
    #    prefer the old way set this to off.
    #
    #Default:
    # log_ip_on_direct on

    #  TAG: mime_table
    #    Pathname to Squid's MIME table. You shouldn't need to change
    #    this, but the default file contains examples and formatting
    #    information if you do.
    #
    #Default:
    # mime_table /usr/local/squid3.0/etc/mime.conf

    #  TAG: log_mime_hdrs    on|off
    #    The Cache can record both the request and the response MIME
    #    headers for each HTTP transaction.  The headers are encoded
    #    safely and will appear as two bracketed fields at the end of
    #    the access log (for either the native or httpd-emulated log
    #    formats).  To enable this logging set log_mime_hdrs to 'on'.
    #
    #Default:
    # log_mime_hdrs off

    #  TAG: useragent_log
    #    Squid will write the User-Agent field from HTTP requests
    #    to the filename specified here.  By default useragent_log
    #    is disabled.
    #
    #Default:
    # none

    #  TAG: referer_log
    #    Squid will write the Referer field from HTTP requests to the
    #    filename specified here.  By default referer_log is disabled.
    #    Note that "referer" is actually a misspelling of "referrer"
    #    however the misspelt version has been accepted into the HTTP RFCs
    #    and we accept both.
    #
    #Default:
    # none

    #  TAG: pid_filename
    #    A filename to write the process-id to.  To disable, enter "none".
    #
    #Default:
    # pid_filename /usr/local/squid3.0/var/logs/squid.pid

    #  TAG: debug_options
    #    Logging options are set as section,level where each source file
    #    is assigned a unique section.  Lower levels result in less
    #    output,  Full debugging (level 9) can result in a very large
    #    log file, so be careful.  The magic word "ALL" sets debugging
    #    levels for all sections.  We recommend normally running with
    #    "ALL,1".
    #
    #Default:
    # debug_options ALL,1

    #  TAG: log_fqdn    on|off
    #    Turn this on if you wish to log fully qualified domain names
    #    in the access.log. To do this Squid does a DNS lookup of all
    #    IP's connecting to it. This can (in some situations) increase
    #    latency, which makes your cache seem slower for interactive
    #    browsing.
    #
    #Default:
    # log_fqdn off

    #  TAG: client_netmask
    #    A netmask for client addresses in logfiles and cachemgr output.
    #    Change this to protect the privacy of your cache clients.
    #    A netmask of 255.255.255.0 will log all IP's in that range with
    #    the last digit set to '0'.
    #
    #Default:
    # client_netmask 255.255.255.255

    #  TAG: forward_log
    # Note: This option is only available if Squid is rebuilt with the
    #       -DWIP_FWD_LOG define
    #
    #    Logs the server-side requests.
    #
    #    This is currently work in progress.
    #
    #Default:
    # none

    #  TAG: strip_query_terms
    #    By default, Squid strips query terms from requested URLs before
    #    logging.  This protects your user's privacy.
    #
    #Default:
    # strip_query_terms on

    #  TAG: buffered_logs    on|off
    #    cache.log log file is written with stdio functions, and as such
    #    it can be buffered or unbuffered. By default it will be unbuffered.
    #    Buffering it can speed up the writing slightly (though you are
    #    unlikely to need to worry unless you run with tons of debugging
    #    enabled in which case performance will suffer badly anyway..).
    #
    #Default:
    # buffered_logs off


    # OPTIONS FOR FTP GATEWAYING
    # -----------------------------------------------------------------------------

    #  TAG: ftp_user
    #    If you want the anonymous login password to be more informative
    #    (and enable the use of picky ftp servers), set this to something
    #    reasonable for your domain, like wwwuser@somewhere.net
    #
    #    The reason why this is domainless by default is the
    #    request can be made on the behalf of a user in any domain,
    #    depending on how the cache is used.
    #    Some ftp server also validate the email address is valid
    #    (for example perl.com).
    #
    #Default:
    # ftp_user Squid@

    #  TAG: ftp_list_width
    #    Sets the width of ftp listings. This should be set to fit in
    #    the width of a standard browser. Setting this too small
    #    can cut off long filenames when browsing ftp sites.
    #
    #Default:
    # ftp_list_width 32

    #  TAG: ftp_passive
    #    If your firewall does not allow Squid to use passive
    #    connections, turn off this option.
    #
    #Default:
    # ftp_passive on

    #  TAG: ftp_sanitycheck
    #    For security and data integrity reasons Squid by default performs
    #    sanity checks of the addresses of FTP data connections ensure the
    #    data connection is to the requested server. If you need to allow
    #    FTP connections to servers using another IP address for the data
    #    connection turn this off.
    #
    #Default:
    # ftp_sanitycheck on

    #  TAG: ftp_telnet_protocol
    #    The FTP protocol is officially defined to use the telnet protocol
    #    as transport channel for the control connection. However, many
    #    implementations are broken and does not respect this aspect of
    #    the FTP protocol.
    #
    #    If you have trouble accessing files with ASCII code 255 in the
    #    path or similar problems involving this ASCII code you can
    #    try setting this directive to off. If that helps, report to the
    #    operator of the FTP server in question that their FTP server
    #    is broken and does not follow the FTP standard.
    #
    #Default:
    # ftp_telnet_protocol on


    # OPTIONS FOR EXTERNAL SUPPORT PROGRAMS
    # -----------------------------------------------------------------------------

    #  TAG: diskd_program
    #    Specify the location of the diskd executable.
    #    Note this is only useful if you have compiled in
    #    diskd as one of the store io modules.
    #
    #Default:
    # diskd_program /usr/local/squid3.0/libexec/diskd

    #  TAG: unlinkd_program
    #    Specify the location of the executable for file deletion process.
    #
    #Default:
    # unlinkd_program /usr/local/squid3.0/libexec/unlinkd

    #  TAG: pinger_program
    #    Specify the location of the executable for the pinger process.
    #
    #Default:
    # pinger_program /usr/local/squid3.0/libexec/pinger


    # OPTIONS FOR URL REWRITING
    # -----------------------------------------------------------------------------

    #  TAG: url_rewrite_program
    #    Specify the location of the executable for the URL rewriter.
    #    Since they can perform almost any function there isn't one included.
    #
    #    For each requested URL rewriter will receive on line with the format
    #
    #    URL <SP> client_ip "/" fqdn <SP> user <SP> method [<SP> kvpairs]<NL>
    #
    #    In the future, the rewriter interface will be extended with
    #    key=value pairs ("kvpairs" shown above).  Rewriter programs
    #    should be prepared to receive and possibly ignore additional
    #    whitespace-separated tokens on each input line.
    #
    #    And the rewriter may return a rewritten URL. The other components of
    #    the request line does not need to be returned (ignored if they are).
    #
    #    The rewriter can also indicate that a client-side redirect should
    #    be performed to the new URL. This is done by prefixing the returned
    #    URL with "301:" (moved permanently) or 302: (moved temporarily).
    #
    #    By default, a URL rewriter is not used.
    #
    #Default:
    # none

    #  TAG: url_rewrite_children
    #    The number of redirector processes to spawn. If you start
    #    too few Squid will have to wait for them to process a backlog of
    #    URLs, slowing it down. If you start too many they will use RAM
    #    and other system resources.
    #
    #Default:
    # url_rewrite_children 5

    #  TAG: url_rewrite_concurrency
    #    The number of requests each redirector helper can handle in
    #    parallel. Defaults to 0 which indicates the redirector
    #    is a old-style single threaded redirector.
    #
    #Default:
    # url_rewrite_concurrency 0

    #  TAG: url_rewrite_host_header
    #    By default Squid rewrites any Host: header in redirected
    #    requests.  If you are running an accelerator this may
    #    not be a wanted effect of a redirector.
    #
    #    WARNING: Entries are cached on the result of the URL rewriting
    #    process, so be careful if you have domain-virtual hosts.
    #
    #Default:
    # url_rewrite_host_header on

    #  TAG: url_rewrite_access
    #    If defined, this access list specifies which requests are
    #    sent to the redirector processes.  By default all requests
    #    are sent.
    #
    #Default:
    # none

    #  TAG: url_rewrite_bypass
    #    When this is 'on', a request will not go through the
    #    redirector if all redirectors are busy.  If this is 'off'
    #    and the redirector queue grows too large, Squid will exit
    #    with a FATAL error and ask you to increase the number of
    #    redirectors.  You should only enable this if the redirectors
    #    are not critical to your caching system.  If you use
    #    redirectors for access control, and you enable this option,
    #    users may have access to pages they should not
    #    be allowed to request.
    #
    #Default:
    # url_rewrite_bypass off


    # OPTIONS FOR TUNING THE CACHE
    # -----------------------------------------------------------------------------

    #  TAG: cache
    #    A list of ACL elements which, if matched and denied, cause the request to
    #    not be satisfied from the cache and the reply to not be cached.
    #    In other words, use this to force certain objects to never be cached.
    #
    #    You must use the words 'allow' or 'deny' to indicate whether items
    #    matching the ACL should be allowed or denied into the cache.
    #
    #    Default is to allow all to be cached
    #
    #Default:
    # none

    #  TAG: refresh_pattern
    #    usage: refresh_pattern [-i] regex min percent max [options]
    #
    #    By default, regular expressions are CASE-SENSITIVE.  To make
    #    them case-insensitive, use the -i option.
    #
    #    'Min' is the time (in minutes) an object without an explicit
    #    expiry time should be considered fresh. The recommended
    #    value is 0, any higher values may cause dynamic applications
    #    to be erroneously cached unless the application designer
    #    has taken the appropriate actions.
    #
    #    'Percent' is a percentage of the objects age (time since last
    #    modification age) an object without explicit expiry time
    #    will be considered fresh.
    #
    #    'Max' is an upper limit on how long objects without an explicit
    #    expiry time will be considered fresh.
    #
    #    options: override-expire
    #         override-lastmod
    #         reload-into-ims
    #         ignore-reload
    #         ignore-no-cache
    #         ignore-no-store
    #         ignore-private
    #         ignore-auth
    #         refresh-ims
    #
    #        override-expire enforces min age even if the server
    #        sent an explicit expiry time (e.g., with the
    #        Expires: header or Cache-Control: max-age). Doing this
    #        VIOLATES the HTTP standard.  Enabling this feature
    #        could make you liable for problems which it causes.
    #
    #        Note: override-expire does not enforce staleness - it only extends
    #        freshness / min. If the server returns a Expires time which
    #        is longer than your max time, Squid will still consider
    #        the object fresh for that period of time.
    #
    #        override-lastmod enforces min age even on objects
    #        that were modified recently.
    #
    #        reload-into-ims changes client no-cache or ``reload''
    #        to If-Modified-Since requests. Doing this VIOLATES the
    #        HTTP standard. Enabling this feature could make you
    #        liable for problems which it causes.
    #
    #        ignore-reload ignores a client no-cache or ``reload''
    #        header. Doing this VIOLATES the HTTP standard. Enabling
    #        this feature could make you liable for problems which
    #        it causes.
    #
    #        ignore-no-cache ignores any ``Pragma: no-cache'' and
    #        ``Cache-control: no-cache'' headers received from a server.
    #        The HTTP RFC never allows the use of this (Pragma) header
    #        from a server, only a client, though plenty of servers
    #        send it anyway.
    #
    #        ignore-no-store ignores any ``Cache-control: no-store''
    #        headers received from a server. Doing this VIOLATES
    #        the HTTP standard. Enabling this feature could make you
    #        liable for problems which it causes.
    #
    #        ignore-private ignores any ``Cache-control: private''
    #        headers received from a server. Doing this VIOLATES
    #        the HTTP standard. Enabling this feature could make you
    #        liable for problems which it causes.
    #
    #        ignore-auth caches responses to requests with authorization,
    #        as if the originserver had sent ``Cache-control: public''
    #        in the response header. Doing this VIOLATES the HTTP standard.
    #        Enabling this feature could make you liable for problems which
    #        it causes.
    #
    #        refresh-ims causes squid to contact the origin server
    #        when a client issues an If-Modified-Since request. This
    #        ensures that the client will receive an updated version
    #        if one is available.
    #
    #    Basically a cached object is:
    #
    #        FRESH if expires < now, else STALE
    #        STALE if age > max
    #        FRESH if lm-factor < percent, else STALE
    #        FRESH if age < min
    #        else STALE
    #
    #    The refresh_pattern lines are checked in the order listed here.
    #    The first entry which matches is used.  If none of the entries
    #    match the default will be used.
    #
    #    Note, you must uncomment all the default lines if you want
    #    to change one. The default setting is only active if none is
    #    used.
    #
    #Suggested default:
    refresh_pattern ^ftp:            1440    20%    10080
    refresh_pattern ^gopher:        1440    0%    1440
    refresh_pattern -i (/cgi-bin/|?)    0    0%    0
    refresh_pattern .            0    20%    4320

    #  TAG: quick_abort_min    (KB)
    #  TAG: quick_abort_max    (KB)
    #  TAG: quick_abort_pct    (percent)
    #    The cache by default continues downloading aborted requests
    #    which are almost completed (less than 16 KB remaining). This
    #    may be undesirable on slow (e.g. SLIP) links and/or very busy
    #    caches.  Impatient users may tie up file descriptors and
    #    bandwidth by repeatedly requesting and immediately aborting
    #    downloads.
    #
    #    When the user aborts a request, Squid will check the
    #    quick_abort values to the amount of data transfered until
    #    then.
    #
    #    If the transfer has less than 'quick_abort_min' KB remaining,
    #    it will finish the retrieval.
    #
    #    If the transfer has more than 'quick_abort_max' KB remaining,
    #    it will abort the retrieval.
    #
    #    If more than 'quick_abort_pct' of the transfer has completed,
    #    it will finish the retrieval.
    #
    #    If you do not want any retrieval to continue after the client
    #    has aborted, set both 'quick_abort_min' and 'quick_abort_max'
    #    to '0 KB'.
    #
    #    If you want retrievals to always continue if they are being
    #    cached set 'quick_abort_min' to '-1 KB'.
    #
    #Default:
    # quick_abort_min 16 KB
    # quick_abort_max 16 KB
    # quick_abort_pct 95

    #  TAG: read_ahead_gap    buffer-size
    #    The amount of data the cache will buffer ahead of what has been
    #    sent to the client when retrieving an object from another server.
    #
    #Default:
    # read_ahead_gap 16 KB

    #  TAG: negative_ttl    time-units
    #    Time-to-Live (TTL) for failed requests.  Certain types of
    #    failures (such as "connection refused" and "404 Not Found") are
    #    negatively-cached for a configurable amount of time.  The
    #    default is 5 minutes.  Note that this is different from
    #    negative caching of DNS lookups.
    #
    #    WARNING: This setting VIOLATES RFC 2616 when non-zero.
    #    If you have problems with eror pages caching, set to '0 seconds'
    #
    #Default:
    # negative_ttl 5 minutes

    #  TAG: positive_dns_ttl    time-units
    #    Upper limit on how long Squid will cache positive DNS responses.
    #    Default is 6 hours (360 minutes). This directive must be set
    #    larger than negative_dns_ttl.
    #
    #Default:
    # positive_dns_ttl 6 hours

    #  TAG: negative_dns_ttl    time-units
    #    Time-to-Live (TTL) for negative caching of failed DNS lookups.
    #    This also sets the lower cache limit on positive lookups.
    #    Minimum value is 1 second, and it is not recommendable to go
    #    much below 10 seconds.
    #
    #Default:
    # negative_dns_ttl 1 minutes

    #  TAG: range_offset_limit    (bytes)
    #    Sets a upper limit on how far into the the file a Range request
    #    may be to cause Squid to prefetch the whole file. If beyond this
    #    limit Squid forwards the Range request as it is and the result
    #    is NOT cached.
    #
    #    This is to stop a far ahead range request (lets say start at 17MB)
    #    from making Squid fetch the whole object up to that point before
    #    sending anything to the client.
    #
    #    A value of -1 causes Squid to always fetch the object from the
    #    beginning so it may cache the result. (2.0 style)
    #
    #    A value of 0 causes Squid to never fetch more than the
    #    client requested. (default)
    #
    #Default:
    # range_offset_limit 0 KB

    #  TAG: minimum_expiry_time    (seconds)
    #    The minimum caching time according to (Expires - Date)
    #    Headers Squid honors if the object can't be revalidated
    #    defaults to 60 seconds. In reverse proxy environments it
    #    might be desirable to honor shorter object lifetimes. It
    #    is most likely better to make your server return a
    #    meaningful Last-Modified header however. In ESI environments
    #    where page fragments often have short lifetimes, this will
    #    often be best set to 0.
    #
    #Default:
    # minimum_expiry_time 60 seconds

    #  TAG: store_avg_object_size    (kbytes)
    #    Average object size, used to estimate number of objects your
    #    cache can hold.  The default is 13 KB.
    #
    #Default:
    # store_avg_object_size 13 KB

    #  TAG: store_objects_per_bucket
    #    Target number of objects per bucket in the store hash table.
    #    Lowering this value increases the total number of buckets and
    #    also the storage maintenance rate.  The default is 20.
    #
    #Default:
    # store_objects_per_bucket 20


    # HTTP OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: request_header_max_size    (KB)
    #    This specifies the maximum size for HTTP headers in a request.
    #    Request headers are usually relatively small (about 512 bytes).
    #    Placing a limit on the request header size will catch certain
    #    bugs (for example with persistent connections) and possibly
    #    buffer-overflow or denial-of-service attacks.
    #
    #Default:
    # request_header_max_size 20 KB

    #  TAG: reply_header_max_size    (KB)
    #    This specifies the maximum size for HTTP headers in a reply.
    #    Reply headers are usually relatively small (about 512 bytes).
    #    Placing a limit on the reply header size will catch certain
    #    bugs (for example with persistent connections) and possibly
    #    buffer-overflow or denial-of-service attacks.
    #
    #Default:
    # reply_header_max_size 20 KB

    #  TAG: request_body_max_size    (bytes)
    #    This specifies the maximum size for an HTTP request body.
    #    In other words, the maximum size of a PUT/POST request.
    #    A user who attempts to send a request with a body larger
    #    than this limit receives an "Invalid Request" error message.
    #    If you set this parameter to a zero (the default), there will
    #    be no limit imposed.
    #
    #Default:
    # request_body_max_size 0 KB

    #  TAG: chunked_request_body_max_size    (bytes)
    #    A broken or confused HTTP/1.1 client may send a chunked HTTP
    #    request to Squid. Squid does not have full support for that
    #    feature yet. To cope with such requests, Squid buffers the
    #    entire request and then dechunks request body to create a
    #    plain HTTP/1.0 request with a known content length. The plain
    #    request is then used by the rest of Squid code as usual.
    #
    #    The option value specifies the maximum size of the buffer used
    #    to hold the request before the conversion. If the chunked
    #    request size exceeds the specified limit, the conversion
    #    fails, and the client receives an "unsupported request" error,
    #    as if dechunking was disabled.
    #
    #    Dechunking is enabled by default. To disable conversion of
    #    chunked requests, set the maximum to zero.
    #
    #    Request dechunking feature and this option in particular are a
    #    temporary hack. When chunking requests and responses are fully
    #    supported, there will be no need to buffer a chunked request.
    #
    #Default:
    # chunked_request_body_max_size 64 KB

    #  TAG: broken_posts
    #    A list of ACL elements which, if matched, causes Squid to send
    #    an extra CRLF pair after the body of a PUT/POST request.
    #
    #    Some HTTP servers has broken implementations of PUT/POST,
    #    and rely on an extra CRLF pair sent by some WWW clients.
    #
    #    Quote from RFC2616 section 4.1 on this matter:
    #
    #      Note: certain buggy HTTP/1.0 client implementations generate an
    #      extra CRLF's after a POST request. To restate what is explicitly
    #      forbidden by the BNF, an HTTP/1.1 client must not preface or follow
    #      a request with an extra CRLF.
    #
    #Example:
    # acl buggy_server url_regex ^http://....
    # broken_posts allow buggy_server
    #
    #Default:
    # none

    #  TAG: via    on|off
    #    If set (default), Squid will include a Via header in requests and
    #    replies as required by RFC2616.
    #
    #Default:
    # via on

    #  TAG: ie_refresh    on|off
    #    Microsoft Internet Explorer up until version 5.5 Service
    #    Pack 1 has an issue with transparent proxies, wherein it
    #    is impossible to force a refresh.  Turning this on provides
    #    a partial fix to the problem, by causing all IMS-REFRESH
    #    requests from older IE versions to check the origin server
    #    for fresh content.  This reduces hit ratio by some amount
    #    (~10% in my experience), but allows users to actually get
    #    fresh content when they want it.  Note because Squid
    #    cannot tell if the user is using 5.5 or 5.5SP1, the behavior
    #    of 5.5 is unchanged from old versions of Squid (i.e. a
    #    forced refresh is impossible).  Newer versions of IE will,
    #    hopefully, continue to have the new behavior and will be
    #    handled based on that assumption.  This option defaults to
    #    the old Squid behavior, which is better for hit ratios but
    #    worse for clients using IE, if they need to be able to
    #    force fresh content.
    #
    #Default:
    # ie_refresh off

    #  TAG: vary_ignore_expire    on|off
    #    Many HTTP servers supporting Vary gives such objects
    #    immediate expiry time with no cache-control header
    #    when requested by a HTTP/1.0 client. This option
    #    enables Squid to ignore such expiry times until
    #    HTTP/1.1 is fully implemented.
    #
    #    WARNING: If turned on this may eventually cause some
    #    varying objects not intended for caching to get cached.
    #
    #Default:
    # vary_ignore_expire off

    #  TAG: extension_methods
    #    Squid only knows about standardized HTTP request methods.
    #    You can add up to 20 additional "extension" methods here.
    #
    #Default:
    # none

    #  TAG: request_entities
    #    Squid defaults to deny GET and HEAD requests with request entities,
    #    as the meaning of such requests are undefined in the HTTP standard
    #    even if not explicitly forbidden.
    #
    #    Set this directive to on if you have clients which insists
    #    on sending request entities in GET or HEAD requests. But be warned
    #    that there is server software (both proxies and web servers) which
    #    can fail to properly process this kind of request which may make you
    #    vulnerable to cache pollution attacks if enabled.
    #
    #Default:
    # request_entities off

    #  TAG: request_header_access
    #    Usage: request_header_access header_name allow|deny [!]aclname ...
    #
    #    WARNING: Doing this VIOLATES the HTTP standard.  Enabling
    #    this feature could make you liable for problems which it
    #    causes.
    #
    #    This option replaces the old 'anonymize_headers' and the
    #    older 'http_anonymizer' option with something that is much
    #    more configurable. This new method creates a list of ACLs
    #    for each header, allowing you very fine-tuned header
    #    mangling.
    #
    #    This option only applies to request headers, i.e., from the
    #    client to the server.
    #
    #    You can only specify known headers for the header name.
    #    Other headers are reclassified as 'Other'. You can also
    #    refer to all the headers with 'All'.
    #
    #    For example, to achieve the same behavior as the old
    #    'http_anonymizer standard' option, you should use:
    #
    #        request_header_access From deny all
    #        request_header_access Referer deny all
    #        request_header_access Server deny all
    #        request_header_access User-Agent deny all
    #        request_header_access WWW-Authenticate deny all
    #        request_header_access Link deny all
    #
    #    Or, to reproduce the old 'http_anonymizer paranoid' feature
    #    you should use:
    #
    #        request_header_access Allow allow all
    #        request_header_access Authorization allow all
    #        request_header_access WWW-Authenticate allow all
    #        request_header_access Proxy-Authorization allow all
    #        request_header_access Proxy-Authenticate allow all
    #        request_header_access Cache-Control allow all
    #        request_header_access Content-Encoding allow all
    #        request_header_access Content-Length allow all
    #        request_header_access Content-Type allow all
    #        request_header_access Date allow all
    #        request_header_access Expires allow all
    #        request_header_access Host allow all
    #        request_header_access If-Modified-Since allow all
    #        request_header_access Last-Modified allow all
    #        request_header_access Location allow all
    #        request_header_access Pragma allow all
    #        request_header_access Accept allow all
    #        request_header_access Accept-Charset allow all
    #        request_header_access Accept-Encoding allow all
    #        request_header_access Accept-Language allow all
    #        request_header_access Content-Language allow all
    #        request_header_access Mime-Version allow all
    #        request_header_access Retry-After allow all
    #        request_header_access Title allow all
    #        request_header_access Connection allow all
    #        request_header_access Proxy-Connection allow all
    #        request_header_access All deny all
    #
    #    although many of those are HTTP reply headers, and so should be
    #    controlled with the reply_header_access directive.
    #
    #    By default, all headers are allowed (no anonymizing is
    #    performed).
    #
    #Default:
    # none

    #  TAG: reply_header_access
    #    Usage: reply_header_access header_name allow|deny [!]aclname ...
    #
    #    WARNING: Doing this VIOLATES the HTTP standard.  Enabling
    #    this feature could make you liable for problems which it
    #    causes.
    #
    #    This option only applies to reply headers, i.e., from the
    #    server to the client.
    #
    #    This is the same as request_header_access, but in the other
    #    direction.
    #
    #    This option replaces the old 'anonymize_headers' and the
    #    older 'http_anonymizer' option with something that is much
    #    more configurable. This new method creates a list of ACLs
    #    for each header, allowing you very fine-tuned header
    #    mangling.
    #
    #    You can only specify known headers for the header name.
    #    Other headers are reclassified as 'Other'. You can also
    #    refer to all the headers with 'All'.
    #
    #    For example, to achieve the same behavior as the old
    #    'http_anonymizer standard' option, you should use:
    #
    #        reply_header_access From deny all
    #        reply_header_access Referer deny all
    #        reply_header_access Server deny all
    #        reply_header_access User-Agent deny all
    #        reply_header_access WWW-Authenticate deny all
    #        reply_header_access Link deny all
    #
    #    Or, to reproduce the old 'http_anonymizer paranoid' feature
    #    you should use:
    #
    #        reply_header_access Allow allow all
    #        reply_header_access Authorization allow all
    #        reply_header_access WWW-Authenticate allow all
    #        reply_header_access Proxy-Authorization allow all
    #        reply_header_access Proxy-Authenticate allow all
    #        reply_header_access Cache-Control allow all
    #        reply_header_access Content-Encoding allow all
    #        reply_header_access Content-Length allow all
    #        reply_header_access Content-Type allow all
    #        reply_header_access Date allow all
    #        reply_header_access Expires allow all
    #        reply_header_access Host allow all
    #        reply_header_access If-Modified-Since allow all
    #        reply_header_access Last-Modified allow all
    #        reply_header_access Location allow all
    #        reply_header_access Pragma allow all
    #        reply_header_access Accept allow all
    #        reply_header_access Accept-Charset allow all
    #        reply_header_access Accept-Encoding allow all
    #        reply_header_access Accept-Language allow all
    #        reply_header_access Content-Language allow all
    #        reply_header_access Mime-Version allow all
    #        reply_header_access Retry-After allow all
    #        reply_header_access Title allow all
    #        reply_header_access Connection allow all
    #        reply_header_access Proxy-Connection allow all
    #        reply_header_access All deny all
    #
    #    although the HTTP request headers won't be usefully controlled
    #    by this directive -- see request_header_access for details.
    #
    #    By default, all headers are allowed (no anonymizing is
    #    performed).
    #
    #Default:
    # none

    #  TAG: request_header_replace
    #    Usage:   request_header_replace header_name message
    #    Example: request_header_replace User-Agent Nutscrape/1.0 (CP/M; 8-bit)
    #
    #    This option allows you to change the contents of headers
    #    denied with request_header_access above, by replacing them
    #    with some fixed string. This replaces the old fake_user_agent
    #    option.
    #
    #    This only applies to request headers, not reply headers.
    #
    #    By default, headers are removed if denied.
    #
    #Default:
    # none

    #  TAG: reply_header_replace
    #        Usage:   reply_header_replace header_name message
    #        Example: reply_header_replace Server Foo/1.0
    #
    #        This option allows you to change the contents of headers
    #        denied with reply_header_access above, by replacing them
    #        with some fixed string.
    #
    #        This only applies to reply headers, not request headers.
    #
    #        By default, headers are removed if denied.
    #
    #Default:
    # none

    #  TAG: relaxed_header_parser    on|off|warn
    #    In the default "on" setting Squid accepts certain forms
    #    of non-compliant HTTP messages where it is unambiguous
    #    what the sending application intended even if the message
    #    is not correctly formatted. The messages is then normalized
    #    to the correct form when forwarded by Squid.
    #
    #    If set to "warn" then a warning will be emitted in cache.log
    #    each time such HTTP error is encountered.
    #
    #    If set to "off" then such HTTP errors will cause the request
    #    or response to be rejected.
    #
    #Default:
    # relaxed_header_parser on


    # TIMEOUTS
    # -----------------------------------------------------------------------------

    #  TAG: forward_timeout    time-units
    #    This parameter specifies how long Squid should at most attempt in
    #    finding a forwarding path for the request before giving up.
    #
    #Default:
    # forward_timeout 4 minutes

    #  TAG: connect_timeout    time-units
    #    This parameter specifies how long to wait for the TCP connect to
    #    the requested server or peer to complete before Squid should
    #    attempt to find another path where to forward the request.
    #
    #Default:
    # connect_timeout 1 minute

    #  TAG: peer_connect_timeout    time-units
    #    This parameter specifies how long to wait for a pending TCP
    #    connection to a peer cache.  The default is 30 seconds.   You
    #    may also set different timeout values for individual neighbors
    #    with the 'connect-timeout' option on a 'cache_peer' line.
    #
    #Default:
    # peer_connect_timeout 30 seconds

    #  TAG: read_timeout    time-units
    #    The read_timeout is applied on server-side connections.  After
    #    each successful read(), the timeout will be extended by this
    #    amount.  If no data is read again after this amount of time,
    #    the request is aborted and logged with ERR_READ_TIMEOUT.  The
    #    default is 15 minutes.
    #
    #Default:
    # read_timeout 15 minutes

    #  TAG: request_timeout
    #    How long to wait for an HTTP request after initial
    #    connection establishment.
    #
    #Default:
    # request_timeout 5 minutes

    #  TAG: persistent_request_timeout
    #    How long to wait for the next HTTP request on a persistent
    #    connection after the previous request completes.
    #
    #Default:
    # persistent_request_timeout 2 minutes

    #  TAG: client_lifetime    time-units
    #    The maximum amount of time a client (browser) is allowed to
    #    remain connected to the cache process.  This protects the Cache
    #    from having a lot of sockets (and hence file descriptors) tied up
    #    in a CLOSE_WAIT state from remote clients that go away without
    #    properly shutting down (either because of a network failure or
    #    because of a poor client implementation).  The default is one
    #    day, 1440 minutes.
    #
    #    NOTE:  The default value is intended to be much larger than any
    #    client would ever need to be connected to your cache.  You
    #    should probably change client_lifetime only as a last resort.
    #    If you seem to have many client connections tying up
    #    filedescriptors, we recommend first tuning the read_timeout,
    #    request_timeout, persistent_request_timeout and quick_abort values.
    #
    #Default:
    # client_lifetime 1 day

    #  TAG: half_closed_clients
    #    Some clients may shutdown the sending side of their TCP
    #    connections, while leaving their receiving sides open.    Sometimes,
    #    Squid can not tell the difference between a half-closed and a
    #    fully-closed TCP connection.
    #
    #    By default, Squid will immediately close client connections when
    #    read(2) returns "no more data to read."
    #
    #    Change this option to 'on' and Squid will keep open connections
    #    until a read(2) or write(2) on the socket returns an error.
    #    This may show some benefits for reverse proxies. But if not
    #    it is recommended to leave OFF.
    #
    #Default:
    # half_closed_clients off

    #  TAG: pconn_timeout
    #    Timeout for idle persistent connections to servers and other
    #    proxies.
    #
    #Default:
    # pconn_timeout 1 minute

    #  TAG: ident_timeout
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-ident-lookups option
    #
    #    Maximum time to wait for IDENT lookups to complete.
    #
    #    If this is too high, and you enabled IDENT lookups from untrusted
    #    users, you might be susceptible to denial-of-service by having
    #    many ident requests going at once.
    #
    #Default:
    # ident_timeout 10 seconds

    #  TAG: shutdown_lifetime    time-units
    #    When SIGTERM or SIGHUP is received, the cache is put into
    #    "shutdown pending" mode until all active sockets are closed.
    #    This value is the lifetime to set for all open descriptors
    #    during shutdown mode.  Any active clients after this many
    #    seconds will receive a 'timeout' message.
    #
    #Default:
    # shutdown_lifetime 30 seconds


    # ADMINISTRATIVE PARAMETERS
    # -----------------------------------------------------------------------------

    #  TAG: cache_mgr
    #    Email-address of local cache manager who will receive
    #    mail if the cache dies.  The default is "webmaster."
    #
    #Default:
    # cache_mgr webmaster

    #  TAG: mail_from
    #    From: email-address for mail sent when the cache dies.
    #    The default is to use 'appname@unique_hostname'.
    #    Default appname value is "squid", can be changed into
    #    src/globals.h before building squid.
    #
    #Default:
    # none

    #  TAG: mail_program
    #    Email program used to send mail if the cache dies.
    #    The default is "mail". The specified program must comply
    #    with the standard Unix mail syntax:
    #      mail-program recipient < mailfile
    #
    #    Optional command line options can be specified.
    #
    #Default:
    # mail_program mail

    #  TAG: cache_effective_user
    #    If you start Squid as root, it will change its effective/real
    #    UID/GID to the user specified below.  The default is to change
    #    to UID of nobody.
    #    see also; cache_effective_group
    #
    #Default:
    # cache_effective_user nobody

    #  TAG: cache_effective_group
    #    Squid sets the GID to the effective user's default group ID
    #    (taken from the password file) and supplementary group list
    #    from the groups membership.
    #
    #    If you want Squid to run with a specific GID regardless of
    #    the group memberships of the effective user then set this
    #    to the group (or GID) you want Squid to run as. When set
    #    all other group privileges of the effective user are ignored
    #    and only this GID is effective. If Squid is not started as
    #    root the user starting Squid MUST be member of the specified
    #    group.
    #
    #    This option is not recommended by the Squid Team.
    #    Our preference is for administrators to configure a secure
    #    user account for squid with UID/GID matching system policies.
    #
    #Default:
    # none

    #  TAG: httpd_suppress_version_string    on|off
    #    Suppress Squid version string info in HTTP headers and HTML error pages.
    #
    #Default:
    # httpd_suppress_version_string off

    #  TAG: visible_hostname
    #    If you want to present a special hostname in error messages, etc,
    #    define this.  Otherwise, the return value of gethostname()
    #    will be used. If you have multiple caches in a cluster and
    #    get errors about IP-forwarding you must set them to have individual
    #    names with this setting.
    #
    #Default:
    # none

    #  TAG: unique_hostname
    #    If you want to have multiple machines with the same
    #    'visible_hostname' you must give each machine a different
    #    'unique_hostname' so forwarding loops can be detected.
    #
    #Default:
    # none

    #  TAG: hostname_aliases
    #    A list of other DNS names your cache has.
    #
    #Default:
    # none

    #  TAG: umask
    #    Minimum umask which should be enforced while the proxy
    #    is running, in addition to the umask set at startup.
    #
    #    For a traditional octal representation of umasks, start
    #        your value with 0.
    #
    #Default:
    # umask 027


    # OPTIONS FOR THE CACHE REGISTRATION SERVICE
    # -----------------------------------------------------------------------------
    #
    #    This section contains parameters for the (optional) cache
    #    announcement service.  This service is provided to help
    #    cache administrators locate one another in order to join or
    #    create cache hierarchies.
    #
    #    An 'announcement' message is sent (via UDP) to the registration
    #    service by Squid.  By default, the announcement message is NOT
    #    SENT unless you enable it with 'announce_period' below.
    #
    #    The announcement message includes your hostname, plus the
    #    following information from this configuration file:
    #
    #        http_port
    #        icp_port
    #        cache_mgr
    #
    #    All current information is processed regularly and made
    #    available on the Web at http://www.ircache.net/Cache/Tracker/.

    #  TAG: announce_period
    #    This is how frequently to send cache announcements.  The
    #    default is `0' which disables sending the announcement
    #    messages.
    #
    #    To enable announcing your cache, just uncomment the line
    #    below.
    #
    #Default:
    # announce_period 0
    #
    #To enable announcing your cache, just uncomment the line below.
    #announce_period 1 day

    #  TAG: announce_host
    #  TAG: announce_file
    #  TAG: announce_port
    #    announce_host and announce_port set the hostname and port
    #    number where the registration message will be sent.
    #
    #    Hostname will default to 'tracker.ircache.net' and port will
    #    default default to 3131.  If the 'filename' argument is given,
    #    the contents of that file will be included in the announce
    #    message.
    #
    #Default:
    # announce_host tracker.ircache.net
    # announce_port 3131


    # HTTPD-ACCELERATOR OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: httpd_accel_surrogate_id
    # Note: This option is only available if Squid is rebuilt with the
    #       -DUSE_SQUID_ESI define
    #
    #    Surrogates (http://www.esi.org/architecture_spec_1.0.html)
    #    need an identification token to allow control targeting. Because
    #    a farm of surrogates may all perform the same tasks, they may share
    #    an identification token.
    #
    #Default:
    # httpd_accel_surrogate_id unset-id

    #  TAG: http_accel_surrogate_remote    on|off
    # Note: This option is only available if Squid is rebuilt with the
    #       -DUSE_SQUID_ESI define
    #
    #    Remote surrogates (such as those in a CDN) honour Surrogate-Control: no-store-remote.
    #    Set this to on to have squid behave as a remote surrogate.
    #
    #Default:
    # http_accel_surrogate_remote off

    #  TAG: esi_parser    libxml2|expat|custom
    # Note: This option is only available if Squid is rebuilt with the
    #       -DUSE_SQUID_ESI define
    #
    #    ESI markup is not strictly XML compatible. The custom ESI parser
    #    will give higher performance, but cannot handle non ASCII character
    #    encodings.
    #
    #Default:
    # esi_parser custom


    # DELAY POOL PARAMETERS
    # -----------------------------------------------------------------------------

    #  TAG: delay_pools
    #    This represents the number of delay pools to be used.  For example,
    #    if you have one class 2 delay pool and one class 3 delays pool, you
    #    have a total of 2 delay pools.
    #
    #Default:
    # delay_pools 0

    #  TAG: delay_class
    #    This defines the class of each delay pool.  There must be exactly one
    #    delay_class line for each delay pool.  For example, to define two
    #    delay pools, one of class 2 and one of class 3, the settings above
    #    and here would be:
    #
    #Example:
    # delay_pools 4      # 4 delay pools
    # delay_class 1 2    # pool 1 is a class 2 pool
    # delay_class 2 3    # pool 2 is a class 3 pool
    # delay_class 3 4    # pool 3 is a class 4 pool
    # delay_class 4 5    # pool 4 is a class 5 pool
    #
    #    The delay pool classes are:
    #
    #        class 1        Everything is limited by a single aggregate
    #                bucket.
    #
    #        class 2     Everything is limited by a single aggregate
    #                bucket as well as an "individual" bucket chosen
    #                from bits 25 through 32 of the IP address.
    #
    #        class 3        Everything is limited by a single aggregate
    #                bucket as well as a "network" bucket chosen
    #                from bits 17 through 24 of the IP address and a
    #                "individual" bucket chosen from bits 17 through
    #                32 of the IP address.
    #
    #        class 4        Everything in a class 3 delay pool, with an
    #                additional limit on a per user basis. This
    #                only takes effect if the username is established
    #                in advance - by forcing authentication in your
    #                http_access rules.
    #
    #        class 5        Requests are grouped according their tag (see
    #                external_acl's tag= reply).
    #
    #    NOTE: If an IP address is a.b.c.d
    #        -> bits 25 through 32 are "d"
    #        -> bits 17 through 24 are "c"
    #        -> bits 17 through 32 are "c * 256 + d"
    #
    #Default:
    # none

    #  TAG: delay_access
    #    This is used to determine which delay pool a request falls into.
    #
    #    delay_access is sorted per pool and the matching starts with pool 1,
    #    then pool 2, ..., and finally pool N. The first delay pool where the
    #    request is allowed is selected for the request. If it does not allow
    #    the request to any pool then the request is not delayed (default).
    #
    #    For example, if you want some_big_clients in delay
    #    pool 1 and lotsa_little_clients in delay pool 2:
    #
    #Example:
    # delay_access 1 allow some_big_clients
    # delay_access 1 deny all
    # delay_access 2 allow lotsa_little_clients
    # delay_access 2 deny all
    # delay_access 3 allow authenticated_clients
    #
    #Default:
    # none

    #  TAG: delay_parameters
    #    This defines the parameters for a delay pool.  Each delay pool has
    #    a number of "buckets" associated with it, as explained in the
    #    description of delay_class.  For a class 1 delay pool, the syntax is:
    #
    #delay_parameters pool aggregate
    #
    #    For a class 2 delay pool:
    #
    #delay_parameters pool aggregate individual
    #
    #    For a class 3 delay pool:
    #
    #delay_parameters pool aggregate network individual
    #
    #    For a class 4 delay pool:
    #
    #delay_parameters pool aggregate network individual user
    #
    #    For a class 5 delay pool:
    #
    #delay_parameters pool tag
    #
    #    The variables here are:
    #
    #        pool        a pool number - ie, a number between 1 and the
    #                number specified in delay_pools as used in
    #                delay_class lines.
    #
    #        aggregate    the "delay parameters" for the aggregate bucket
    #                (class 1, 2, 3).
    #
    #        individual    the "delay parameters" for the individual
    #                buckets (class 2, 3).
    #
    #        network        the "delay parameters" for the network buckets
    #                (class 3).
    #
    #        user        the delay parameters for the user buckets
    #                (class 4).
    #
    #        tag        the delay parameters for the tag buckets
    #                (class 5).
    #
    #    A pair of delay parameters is written restore/maximum, where restore is
    #    the number of bytes (not bits - modem and network speeds are usually
    #    quoted in bits) per second placed into the bucket, and maximum is the
    #    maximum number of bytes which can be in the bucket at any time.
    #
    #    For example, if delay pool number 1 is a class 2 delay pool as in the
    #    above example, and is being used to strictly limit each host to 64kbps
    #    (plus overheads), with no overall limit, the line is:
    #
    #delay_parameters 1 -1/-1 8000/8000
    #
    #    Note that the figure -1 is used to represent "unlimited".
    #
    #    And, if delay pool number 2 is a class 3 delay pool as in the above
    #    example, and you want to limit it to a total of 256kbps (strict limit)
    #    with each 8-bit network permitted 64kbps (strict limit) and each
    #    individual host permitted 4800bps with a bucket maximum size of 64kb
    #    to permit a decent web page to be downloaded at a decent speed
    #    (if the network is not being limited due to overuse) but slow down
    #    large downloads more significantly:
    #
    #delay_parameters 2 32000/32000 8000/8000 600/8000
    #
    #    There must be one delay_parameters line for each delay pool.
    #
    #    Finally, for a class 4 delay pool as in the example - each user will
    #    be limited to 128Kb no matter how many workstations they are logged into.:
    #
    #delay_parameters 4 32000/32000 8000/8000 600/64000 16000/16000
    #
    #Default:
    # none

    #  TAG: delay_initial_bucket_level    (percent, 0-100)
    #    The initial bucket percentage is used to determine how much is put
    #    in each bucket when squid starts, is reconfigured, or first notices
    #    a host accessing it (in class 2 and class 3, individual hosts and
    #    networks only have buckets associated with them once they have been
    #    "seen" by squid).
    #
    #Default:
    # delay_initial_bucket_level 50


    # WCCPv1 AND WCCPv2 CONFIGURATION OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: wccp_router
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccp option
    #
    #  TAG: wccp2_router
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    Use this option to define your WCCP ``home'' router for
    #    Squid.
    #
    #    wccp_router supports a single WCCP(v1) router
    #
    #    wccp2_router supports multiple WCCPv2 routers
    #
    #    only one of the two may be used at the same time and defines
    #    which version of WCCP to use.
    #
    #Default:
    # wccp_router 0.0.0.0

    #  TAG: wccp_version
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccp option
    #
    #    This directive is only relevant if you need to set up WCCP(v1)
    #    to some very old and end-of-life Cisco routers. In all other
    #    setups it must be left unset or at the default setting.
    #    It defines an internal version in the WCCP(v1) protocol,
    #    with version 4 being the officially documented protocol.
    #
    #    According to some users, Cisco IOS 11.2 and earlier only
    #    support WCCP version 3.  If you're using that or an earlier
    #    version of IOS, you may need to change this value to 3, otherwise
    #    do not specify this parameter.
    #
    #Default:
    # wccp_version 4

    #  TAG: wccp2_rebuild_wait
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    If this is enabled Squid will wait for the cache dir rebuild to finish
    #    before sending the first wccp2 HereIAm packet
    #
    #Default:
    # wccp2_rebuild_wait on

    #  TAG: wccp2_forwarding_method
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    WCCP2 allows the setting of forwarding methods between the
    #    router/switch and the cache.  Valid values are as follows:
    #
    #    1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
    #    2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
    #
    #    Currently (as of IOS 12.4) cisco routers only support GRE.
    #    Cisco switches only support the L2 redirect assignment method.
    #
    #Default:
    # wccp2_forwarding_method 1

    #  TAG: wccp2_return_method
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    WCCP2 allows the setting of return methods between the
    #    router/switch and the cache for packets that the cache
    #    decides not to handle.  Valid values are as follows:
    #
    #    1 - GRE encapsulation (forward the packet in a GRE/WCCP tunnel)
    #    2 - L2 redirect (forward the packet using Layer 2/MAC rewriting)
    #
    #    Currently (as of IOS 12.4) cisco routers only support GRE.
    #    Cisco switches only support the L2 redirect assignment.
    #
    #    If the "ip wccp redirect exclude in" command has been
    #    enabled on the cache interface, then it is still safe for
    #    the proxy server to use a l2 redirect method even if this
    #    option is set to GRE.
    #
    #Default:
    # wccp2_return_method 1

    #  TAG: wccp2_assignment_method
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    WCCP2 allows the setting of methods to assign the WCCP hash
    #    Valid values are as follows:
    #
    #    1 - Hash assignment
    #    2 - Mask assignment
    #
    #    As a general rule, cisco routers support the hash assignment method
    #    and cisco switches support the mask assignment method.
    #
    #Default:
    # wccp2_assignment_method 1

    #  TAG: wccp2_service
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    WCCP2 allows for multiple traffic services. There are two
    #    types: "standard" and "dynamic". The standard type defines
    #    one service id - http (id 0). The dynamic service ids can be from
    #    51 to 255 inclusive.  In order to use a dynamic service id
    #    one must define the type of traffic to be redirected; this is done
    #    using the wccp2_service_info option.
    #
    #    The "standard" type does not require a wccp2_service_info option,
    #    just specifying the service id will suffice.
    #
    #    MD5 service authentication can be enabled by adding
    #    "password=<password>" to the end of this service declaration.
    #
    #    Examples:
    #
    #    wccp2_service standard 0    # for the 'web-cache' standard service
    #    wccp2_service dynamic 80    # a dynamic service type which will be
    #                    # fleshed out with subsequent options.
    #    wccp2_service standard 0 password=foo
    #
    #
    #Default:
    # wccp2_service standard 0

    #  TAG: wccp2_service_info
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    Dynamic WCCPv2 services require further information to define the
    #    traffic you wish to have diverted.
    #
    #    The format is:
    #
    #    wccp2_service_info <id> protocol=<protocol> flags=<flag>,<flag>..
    #        priority=<priority> ports=<port>,<port>..
    #
    #    The relevant WCCPv2 flags:
    #    + src_ip_hash, dst_ip_hash
    #    + source_port_hash, dst_port_hash
    #    + src_ip_alt_hash, dst_ip_alt_hash
    #    + src_port_alt_hash, dst_port_alt_hash
    #    + ports_source
    #
    #    The port list can be one to eight entries.
    #
    #    Example:
    #
    #    wccp2_service_info 80 protocol=tcp flags=src_ip_hash,ports_source
    #        priority=240 ports=80
    #
    #    Note: the service id must have been defined by a previous
    #    'wccp2_service dynamic <id>' entry.
    #
    #Default:
    # none

    #  TAG: wccp2_weight
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    Each cache server gets assigned a set of the destination
    #    hash proportional to their weight.
    #
    #Default:
    # wccp2_weight 10000

    #  TAG: wccp_address
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccp option
    #
    #  TAG: wccp2_address
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-wccpv2 option
    #
    #    Use this option if you require WCCP to use a specific
    #    interface address.
    #
    #    The default behavior is to not bind to any specific address.
    #
    #Default:
    # wccp_address 0.0.0.0
    # wccp2_address 0.0.0.0


    # PERSISTENT CONNECTION HANDLING
    # -----------------------------------------------------------------------------
    #
    # Also see "pconn_timeout" in the TIMEOUTS section

    #  TAG: client_persistent_connections
    #  TAG: server_persistent_connections
    #    Persistent connection support for clients and servers.  By
    #    default, Squid uses persistent connections (when allowed)
    #    with its clients and servers.  You can use these options to
    #    disable persistent connections with clients and/or servers.
    #
    #Default:
    # client_persistent_connections on
    # server_persistent_connections on

    #  TAG: persistent_connection_after_error
    #    With this directive the use of persistent connections after
    #    HTTP errors can be disabled. Useful if you have clients
    #    who fail to handle errors on persistent connections proper.
    #
    #Default:
    # persistent_connection_after_error off

    #  TAG: detect_broken_pconn
    #    Some servers have been found to incorrectly signal the use
    #    of HTTP/1.0 persistent connections even on replies not
    #    compatible, causing significant delays. This server problem
    #    has mostly been seen on redirects.
    #
    #    By enabling this directive Squid attempts to detect such
    #    broken replies and automatically assume the reply is finished
    #    after 10 seconds timeout.
    #
    #Default:
    # detect_broken_pconn off


    # CACHE DIGEST OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: digest_generation
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-cache-digests option
    #
    #    This controls whether the server will generate a Cache Digest
    #    of its contents.  By default, Cache Digest generation is
    #    enabled if Squid is compiled with --enable-cache-digests defined.
    #
    #Default:
    # digest_generation on

    #  TAG: digest_bits_per_entry
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-cache-digests option
    #
    #    This is the number of bits of the server's Cache Digest which
    #    will be associated with the Digest entry for a given HTTP
    #    Method and URL (public key) combination.  The default is 5.
    #
    #Default:
    # digest_bits_per_entry 5

    #  TAG: digest_rebuild_period    (seconds)
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-cache-digests option
    #
    #    This is the wait time between Cache Digest rebuilds.
    #
    #Default:
    # digest_rebuild_period 1 hour

    #  TAG: digest_rewrite_period    (seconds)
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-cache-digests option
    #
    #    This is the wait time between Cache Digest writes to
    #    disk.
    #
    #Default:
    # digest_rewrite_period 1 hour

    #  TAG: digest_swapout_chunk_size    (bytes)
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-cache-digests option
    #
    #    This is the number of bytes of the Cache Digest to write to
    #    disk at a time.  It defaults to 4096 bytes (4KB), the Squid
    #    default swap page.
    #
    #Default:
    # digest_swapout_chunk_size 4096 bytes

    #  TAG: digest_rebuild_chunk_percentage    (percent, 0-100)
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-cache-digests option
    #
    #    This is the percentage of the Cache Digest to be scanned at a
    #    time.  By default it is set to 10% of the Cache Digest.
    #
    #Default:
    # digest_rebuild_chunk_percentage 10


    # SNMP OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: snmp_port
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-snmp option
    #
    #    The port number where Squid listens for SNMP requests. To enable
    #    SNMP support set this to a suitable port number. Port number
    #    3401 is often used for the Squid SNMP agent. By default it's
    #    set to "0" (disabled)
    #Default:
    # snmp_port 0
    #
    #snmp_port 3401

    #  TAG: snmp_access
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-snmp option
    #
    #    Allowing or denying access to the SNMP port.
    #
    #    All access to the agent is denied by default.
    #    usage:
    #
    #    snmp_access allow|deny [!]aclname ...
    #
    #Example:
    # snmp_access allow snmppublic localhost
    # snmp_access deny all
    #
    #Default:
    # snmp_access deny all

    #  TAG: snmp_incoming_address
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-snmp option
    #
    #  TAG: snmp_outgoing_address
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-snmp option
    #
    #    Just like 'udp_incoming_address' above, but for the SNMP port.
    #
    #    snmp_incoming_address    is used for the SNMP socket receiving
    #                messages from SNMP agents.
    #    snmp_outgoing_address    is used for SNMP packets returned to SNMP
    #                agents.
    #
    #    The default snmp_incoming_address (0.0.0.0) is to listen on all
    #    available network interfaces.
    #
    #    If snmp_outgoing_address is set to 255.255.255.255 (the default)
    #    it will use the same socket as snmp_incoming_address. Only
    #    change this if you want to have SNMP replies sent using another
    #    address than where this Squid listens for SNMP queries.
    #
    #    NOTE, snmp_incoming_address and snmp_outgoing_address can not have
    #    the same value since they both use port 3401.
    #
    #Default:
    # snmp_incoming_address 0.0.0.0
    # snmp_outgoing_address 255.255.255.255


    # ICP OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: icp_port
    #    The port number where Squid sends and receives ICP queries to
    #    and from neighbor caches.  The standard UDP port for ICP is 3130.
    #    Default is disabled (0).
    #Default:
    # icp_port 0
    #
    icp_port 3130

    #  TAG: htcp_port
    #    The port number where Squid sends and receives HTCP queries to
    #    and from neighbor caches.  To turn it on you want to set it to
    #    4827. By default it is set to "0" (disabled).
    #Default:
    # htcp_port 0
    #
    #htcp_port 4827

    #  TAG: log_icp_queries    on|off
    #    If set, ICP queries are logged to access.log. You may wish
    #    do disable this if your ICP load is VERY high to speed things
    #    up or to simplify log analysis.
    #
    #Default:
    # log_icp_queries on

    #  TAG: udp_incoming_address
    #    udp_incoming_address    is used for UDP packets received from other
    #                caches.
    #
    #    The default behavior is to not bind to any specific address.
    #
    #    Only change this if you want to have all UDP queries received on
    #    a specific interface/address.
    #
    #    NOTE: udp_incoming_address is used by the ICP, HTCP, and DNS
    #    modules. Altering it will affect all of them in the same manner.
    #
    #    see also; udp_outgoing_address
    #
    #    NOTE, udp_incoming_address and udp_outgoing_address can not
    #    have the same value since they both use the same port.
    #
    #Default:
    # udp_incoming_address 0.0.0.0

    #  TAG: udp_outgoing_address
    #    udp_outgoing_address    is used for UDP packets sent out to other
    #                caches.
    #
    #    The default behavior is to not bind to any specific address.
    #
    #    Instead it will use the same socket as udp_incoming_address.
    #    Only change this if you want to have UDP queries sent using another
    #    address than where this Squid listens for UDP queries from other
    #    caches.
    #
    #    NOTE: udp_outgoing_address is used by the ICP, HTCP, and DNS
    #    modules. Altering it will affect all of them in the same manner.
    #
    #    see also; udp_incoming_address
    #
    #    NOTE, udp_incoming_address and udp_outgoing_address can not
    #    have the same value since they both use the same port.
    #
    #Default:
    # udp_outgoing_address 255.255.255.255

    #  TAG: icp_hit_stale    on|off
    #    If you want to return ICP_HIT for stale cache objects, set this
    #    option to 'on'.  If you have sibling relationships with caches
    #    in other administrative domains, this should be 'off'.  If you only
    #    have sibling relationships with caches under your control,
    #    it is probably okay to set this to 'on'.
    #    If set to 'on', your siblings should use the option "allow-miss"
    #    on their cache_peer lines for connecting to you.
    #
    #Default:
    # icp_hit_stale off

    #  TAG: minimum_direct_hops
    #    If using the ICMP pinging stuff, do direct fetches for sites
    #    which are no more than this many hops away.
    #
    #Default:
    # minimum_direct_hops 4

    #  TAG: minimum_direct_rtt
    #    If using the ICMP pinging stuff, do direct fetches for sites
    #    which are no more than this many rtt milliseconds away.
    #
    #Default:
    # minimum_direct_rtt 400

    #  TAG: netdb_low
    #  TAG: netdb_high
    #    The low and high water marks for the ICMP measurement
    #    database.  These are counts, not percents.  The defaults are
    #    900 and 1000.  When the high water mark is reached, database
    #    entries will be deleted until the low mark is reached.
    #
    #Default:
    # netdb_low 900
    # netdb_high 1000

    #  TAG: netdb_ping_period
    #    The minimum period for measuring a site.  There will be at
    #    least this much delay between successive pings to the same
    #    network.  The default is five minutes.
    #
    #Default:
    # netdb_ping_period 5 minutes

    #  TAG: query_icmp    on|off
    #    If you want to ask your peers to include ICMP data in their ICP
    #    replies, enable this option.
    #
    #    If your peer has configured Squid (during compilation) with
    #    '--enable-icmp' that peer will send ICMP pings to origin server
    #    sites of the URLs it receives.  If you enable this option the
    #    ICP replies from that peer will include the ICMP data (if available).
    #    Then, when choosing a parent cache, Squid will choose the parent with
    #    the minimal RTT to the origin server.  When this happens, the
    #    hierarchy field of the access.log will be
    #    "CLOSEST_PARENT_MISS".  This option is off by default.
    #
    #Default:
    # query_icmp off

    #  TAG: test_reachability    on|off
    #    When this is 'on', ICP MISS replies will be ICP_MISS_NOFETCH
    #    instead of ICP_MISS if the target host is NOT in the ICMP
    #    database, or has a zero RTT.
    #
    #Default:
    # test_reachability off

    #  TAG: icp_query_timeout    (msec)
    #    Normally Squid will automatically determine an optimal ICP
    #    query timeout value based on the round-trip-time of recent ICP
    #    queries.  If you want to override the value determined by
    #    Squid, set this 'icp_query_timeout' to a non-zero value.  This
    #    value is specified in MILLISECONDS, so, to use a 2-second
    #    timeout (the old default), you would write:
    #
    #        icp_query_timeout 2000
    #
    #Default:
    # icp_query_timeout 0

    #  TAG: maximum_icp_query_timeout    (msec)
    #    Normally the ICP query timeout is determined dynamically.  But
    #    sometimes it can lead to very large values (say 5 seconds).
    #    Use this option to put an upper limit on the dynamic timeout
    #    value.  Do NOT use this option to always use a fixed (instead
    #    of a dynamic) timeout value. To set a fixed timeout see the
    #    'icp_query_timeout' directive.
    #
    #Default:
    # maximum_icp_query_timeout 2000

    #  TAG: minimum_icp_query_timeout    (msec)
    #    Normally the ICP query timeout is determined dynamically.  But
    #    sometimes it can lead to very small timeouts, even lower than
    #    the normal latency variance on your link due to traffic.
    #    Use this option to put an lower limit on the dynamic timeout
    #    value.  Do NOT use this option to always use a fixed (instead
    #    of a dynamic) timeout value. To set a fixed timeout see the
    #    'icp_query_timeout' directive.
    #
    #Default:
    # minimum_icp_query_timeout 5

    #  TAG: background_ping_rate    time-units
    #    Controls how often the ICP pings are sent to siblings that
    #    have background-ping set.
    #
    #Default:
    # background_ping_rate 10 seconds


    # MULTICAST ICP OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: mcast_groups
    #    This tag specifies a list of multicast groups which your server
    #    should join to receive multicasted ICP queries.
    #
    #    NOTE!  Be very careful what you put here!  Be sure you
    #    understand the difference between an ICP _query_ and an ICP
    #    _reply_.  This option is to be set only if you want to RECEIVE
    #    multicast queries.  Do NOT set this option to SEND multicast
    #    ICP (use cache_peer for that).  ICP replies are always sent via
    #    unicast, so this option does not affect whether or not you will
    #    receive replies from multicast group members.
    #
    #    You must be very careful to NOT use a multicast address which
    #    is already in use by another group of caches.
    #
    #    If you are unsure about multicast, please read the Multicast
    #    chapter in the Squid FAQ (http://www.squid-cache.org/FAQ/).
    #
    #    Usage: mcast_groups 239.128.16.128 224.0.1.20
    #
    #    By default, Squid doesn't listen on any multicast groups.
    #
    #Default:
    # none

    #  TAG: mcast_miss_addr
    # Note: This option is only available if Squid is rebuilt with the
    #       -DMULTICAST_MISS_STREAM define
    #
    #    If you enable this option, every "cache miss" URL will
    #    be sent out on the specified multicast address.
    #
    #    Do not enable this option unless you are are absolutely
    #    certain you understand what you are doing.
    #
    #Default:
    # mcast_miss_addr 255.255.255.255

    #  TAG: mcast_miss_ttl
    # Note: This option is only available if Squid is rebuilt with the
    #       -DMULTICAST_MISS_STREAM define
    #
    #    This is the time-to-live value for packets multicasted
    #    when multicasting off cache miss URLs is enabled.  By
    #    default this is set to 'site scope', i.e. 16.
    #
    #Default:
    # mcast_miss_ttl 16

    #  TAG: mcast_miss_port
    # Note: This option is only available if Squid is rebuilt with the
    #       -DMULTICAST_MISS_STREAM define
    #
    #    This is the port number to be used in conjunction with
    #    'mcast_miss_addr'.
    #
    #Default:
    # mcast_miss_port 3135

    #  TAG: mcast_miss_encode_key
    # Note: This option is only available if Squid is rebuilt with the
    #       -DMULTICAST_MISS_STREAM define
    #
    #    The URLs that are sent in the multicast miss stream are
    #    encrypted.  This is the encryption key.
    #
    #Default:
    # mcast_miss_encode_key XXXXXXXXXXXXXXXX

    #  TAG: mcast_icp_query_timeout    (msec)
    #    For multicast peers, Squid regularly sends out ICP "probes" to
    #    count how many other peers are listening on the given multicast
    #    address.  This value specifies how long Squid should wait to
    #    count all the replies.  The default is 2000 msec, or 2
    #    seconds.
    #
    #Default:
    # mcast_icp_query_timeout 2000


    # INTERNAL ICON OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: icon_directory
    #    Where the icons are stored. These are normally kept in
    #    /usr/local/squid3.0/share/icons
    #
    #Default:
    # icon_directory /usr/local/squid3.0/share/icons

    #  TAG: global_internal_static
    #    This directive controls is Squid should intercept all requests for
    #    /squid-internal-static/ no matter which host the URL is requesting
    #    (default on setting), or if nothing special should be done for
    #    such URLs (off setting). The purpose of this directive is to make
    #    icons etc work better in complex cache hierarchies where it may
    #    not always be possible for all corners in the cache mesh to reach
    #    the server generating a directory listing.
    #
    #Default:
    # global_internal_static on

    #  TAG: short_icon_urls
    #    If this is enabled Squid will use short URLs for icons.
    #    If disabled it will revert to the old behavior of including
    #    it's own name and port in the URL.
    #
    #    If you run a complex cache hierarchy with a mix of Squid and
    #    other proxies you may need to disable this directive.
    #
    #Default:
    # short_icon_urls on


    # ERROR PAGE OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: error_directory
    #    If you wish to create your own versions of the default files, to
    #    customize them to suit your company copy the template files to
    #    another directory and point this tag at them.
    #
    #    Current Language updates can be downloaded from:
    #        http://www.squid-cache.org/Versions/langpack/
    #
    #    The squid developers are interested in making squid available in
    #    a wide variety of languages. If you are making translations for a
    #    langauge that Squid does not currently provide please consider
    #    contributing your translation back to the project.
    #    see http://wiki.squid-cache.org/Translations
    #
    #Default:
    # error_directory /usr/local/squid3.0/share/errors/English

    #  TAG: err_html_text
    #    HTML text to include in error messages.  Make this a "mailto"
    #    URL to your admin address, or maybe just a link to your
    #    organizations Web page.
    #
    #    To include this in your error messages, you must rewrite
    #    the error template files (found in the "errors" directory).
    #    Wherever you want the 'err_html_text' line to appear,
    #    insert a %L tag in the error template file.
    #
    #Default:
    # none

    #  TAG: email_err_data    on|off
    #    If enabled, information about the occurred error will be
    #    included in the mailto links of the ERR pages (if %W is set)
    #    so that the email body contains the data.
    #    Syntax is <A HREF="mailto:%w%W">%w</A>
    #
    #Default:
    # email_err_data on

    #  TAG: deny_info
    #    Usage:   deny_info err_page_name acl
    #    or       deny_info http://... acl
    #    Example: deny_info ERR_CUSTOM_ACCESS_DENIED bad_guys
    #
    #    This can be used to return a ERR_ page for requests which
    #    do not pass the 'http_access' rules.  Squid remembers the last
    #    acl it evaluated in http_access, and if a 'deny_info' line exists
    #    for that ACL Squid returns a corresponding error page.
    #
    #    The acl is typically the last acl on the http_access deny line which
    #    denied access. The exceptions to this rule are:
    #    - When Squid needs to request authentication credentials. It's then
    #      the first authentication related acl encountered
    #    - When none of the http_access lines matches. It's then the last
    #      acl processed on the last http_access line.
    #
    #    You may use ERR_ pages that come with Squid or create your own pages
    #    and put them into the configured errors/ directory.
    #
    #    Alternatively you can specify an error URL. The browsers will
    #    get redirected (302) to the specified URL. %s in the redirection
    #    URL will be replaced by the requested URL.
    #
    #    Alternatively you can tell Squid to reset the TCP connection
    #    by specifying TCP_RESET.
    #
    #Default:
    # none


    # OPTIONS INFLUENCING REQUEST FORWARDING
    # -----------------------------------------------------------------------------

    #  TAG: nonhierarchical_direct
    #    By default, Squid will send any non-hierarchical requests
    #    (matching hierarchy_stoplist or not cacheable request type) direct
    #    to origin servers.
    #
    #    If you set this to off, Squid will prefer to send these
    #    requests to parents.
    #
    #    Note that in most configurations, by turning this off you will only
    #    add latency to these request without any improvement in global hit
    #    ratio.
    #
    #    If you are inside an firewall see never_direct instead of
    #    this directive.
    #
    #Default:
    # nonhierarchical_direct on

    #  TAG: prefer_direct
    #    Normally Squid tries to use parents for most requests. If you for some
    #    reason like it to first try going direct and only use a parent if
    #    going direct fails set this to on.
    #
    #    By combining nonhierarchical_direct off and prefer_direct on you
    #    can set up Squid to use a parent as a backup path if going direct
    #    fails.
    #
    #    Note: If you want Squid to use parents for all requests see
    #    the never_direct directive. prefer_direct only modifies how Squid
    #    acts on cacheable requests.
    #
    #Default:
    # prefer_direct off

    #  TAG: always_direct
    #    Usage: always_direct allow|deny [!]aclname ...
    #
    #    Here you can use ACL elements to specify requests which should
    #    ALWAYS be forwarded by Squid to the origin servers without using
    #    any peers.  For example, to always directly forward requests for
    #    local servers ignoring any parents or siblings you may have use
    #    something like:
    #
    #        acl local-servers dstdomain my.domain.net
    #        always_direct allow local-servers
    #
    #    To always forward FTP requests directly, use
    #
    #        acl FTP proto FTP
    #        always_direct allow FTP
    #
    #    NOTE: There is a similar, but opposite option named
    #    'never_direct'.  You need to be aware that "always_direct deny
    #    foo" is NOT the same thing as "never_direct allow foo".  You
    #    may need to use a deny rule to exclude a more-specific case of
    #    some other rule.  Example:
    #
    #        acl local-external dstdomain external.foo.net
    #        acl local-servers dstdomain  .foo.net
    #        always_direct deny local-external
    #        always_direct allow local-servers
    #
    #    NOTE: If your goal is to make the client forward the request
    #    directly to the origin server bypassing Squid then this needs
    #    to be done in the client configuration. Squid configuration
    #    can only tell Squid how Squid should fetch the object.
    #
    #    NOTE: This directive is not related to caching. The replies
    #    is cached as usual even if you use always_direct. To not cache
    #    the replies see no_cache.
    #
    #    This option replaces some v1.1 options such as local_domain
    #    and local_ip.
    #
    #Default:
    # none

    #  TAG: never_direct
    #    Usage: never_direct allow|deny [!]aclname ...
    #
    #    never_direct is the opposite of always_direct.  Please read
    #    the description for always_direct if you have not already.
    #
    #    With 'never_direct' you can use ACL elements to specify
    #    requests which should NEVER be forwarded directly to origin
    #    servers.  For example, to force the use of a proxy for all
    #    requests, except those in your local domain use something like:
    #
    #        acl local-servers dstdomain .foo.net
    #        never_direct deny local-servers
    #        never_direct allow all
    #
    #    or if Squid is inside a firewall and there are local intranet
    #    servers inside the firewall use something like:
    #
    #        acl local-intranet dstdomain .foo.net
    #        acl local-external dstdomain external.foo.net
    #        always_direct deny local-external
    #        always_direct allow local-intranet
    #        never_direct allow all
    #
    #    This option replaces some v1.1 options such as inside_firewall
    #    and firewall_ip.
    #
    #Default:
    # none


    # ADVANCED NETWORKING OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: incoming_icp_average
    #  TAG: incoming_http_average
    #  TAG: incoming_dns_average
    #  TAG: min_icp_poll_cnt
    #  TAG: min_dns_poll_cnt
    #  TAG: min_http_poll_cnt
    #    Heavy voodoo here.  I can't even believe you are reading this.
    #    Are you crazy?  Don't even think about adjusting these unless
    #    you understand the algorithms in comm_select.c first!
    #
    #Default:
    # incoming_icp_average 6
    # incoming_http_average 4
    # incoming_dns_average 4
    # min_icp_poll_cnt 8
    # min_dns_poll_cnt 8
    # min_http_poll_cnt 8

    #  TAG: accept_filter
    #    FreeBSD:
    #
    #    The name of an accept(2) filter to install on Squid's
    #    listen socket(s).  This feature is perhaps specific to
    #    FreeBSD and requires support in the kernel.
    #
    #    The 'httpready' filter delays delivering new connections
    #    to Squid until a full HTTP request has been received.
    #    See the accf_http(9) man page for details.
    #
    #    The 'dataready' filter delays delivering new connections
    #    to Squid until there is some data to process.
    #    See the accf_dataready(9) man page for details.
    #
    #    Linux:
    #   
    #    The 'data' filter delays delivering of new connections
    #    to Squid until there is some data to process by TCP_ACCEPT_DEFER.
    #    You may optionally specify a number of seconds to wait by
    #    'data=N' where N is the number of seconds. Defaults to 30
    #    if not specified.  See the tcp(7) man page for details.
    #EXAMPLE:
    ## FreeBSD
    #accept_filter httpready
    ## Linux
    #accept_filter data
    #
    #Default:
    # none

    #  TAG: client_ip_max_connections
    #    Set an absolute limit on the number of connections a single
    #    client IP can use. Any more than this and Squid will begin to drop
    #    new connections from the client until it closes some links.
    #
    #    Note that this is a global limit. It affects all HTTP, HTCP, Gopher and FTP
    #    connections from the client. For finer control use the ACL access controls.
    #
    #    Requires client_db to be enabled (the default).
    #
    #    WARNING: This may noticably slow down traffic received via external proxies
    #    or NAT devices and cause them to rebound error messages back to their clients.
    #
    #Default:
    # client_ip_max_connections -1

    #  TAG: tcp_recv_bufsize    (bytes)
    #    Size of receive buffer to set for TCP sockets.  Probably just
    #    as easy to change your kernel's default.  Set to zero to use
    #    the default buffer size.
    #
    #Default:
    # tcp_recv_bufsize 0 bytes


    # ICAP OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: icap_enable    on|off
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    If you want to enable the ICAP module support, set this to on.
    #
    #Default:
    # icap_enable off

    #  TAG: icap_connect_timeout
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    This parameter specifies how long to wait for the TCP connect to
    #    the requested ICAP server to complete before giving up and either
    #    terminating the HTTP transaction or bypassing the failure.
    #
    #    The default for optional services is peer_connect_timeout.
    #    The default for essential services is connect_timeout.
    #    If this option is explicitly set, its value applies to all services.
    #
    #Default:
    # none

    #  TAG: icap_io_timeout    time-units
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    This parameter specifies how long to wait for an I/O activity on
    #    an established, active ICAP connection before giving up and
    #    either terminating the HTTP transaction or bypassing the
    #    failure.
    #
    #    The default is read_timeout.
    #
    #Default:
    # none

    #  TAG: icap_service_failure_limit
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    The limit specifies the number of failures that Squid tolerates
    #    when establishing a new TCP connection with an ICAP service. If
    #    the number of failures exceeds the limit, the ICAP service is
    #    not used for new ICAP requests until it is time to refresh its
    #    OPTIONS. The per-service failure counter is reset to zero each
    #    time Squid fetches new service OPTIONS.
    #
    #    A negative value disables the limit. Without the limit, an ICAP
    #    service will not be considered down due to connectivity failures
    #    between ICAP OPTIONS requests.
    #
    #Default:
    # icap_service_failure_limit 10

    #  TAG: icap_service_revival_delay
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    The delay specifies the number of seconds to wait after an ICAP
    #    OPTIONS request failure before requesting the options again. The
    #    failed ICAP service is considered "down" until fresh OPTIONS are
    #    fetched.
    #
    #    The actual delay cannot be smaller than the hardcoded minimum
    #    delay of 30 seconds.
    #
    #Default:
    # icap_service_revival_delay 180

    #  TAG: icap_preview_enable    on|off
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    The ICAP Preview feature allows the ICAP server to handle the
    #    HTTP message by looking only at the beginning of the message body
    #    or even without receiving the body at all. In some environments,
    #    previews greatly speedup ICAP processing.
    #
    #    During an ICAP OPTIONS transaction, the server may tell    Squid what
    #    HTTP messages should be previewed and how big the preview should be.
    #    Squid will not use Preview if the server did not request one.
    #
    #    To disable ICAP Preview for all ICAP services, regardless of
    #    individual ICAP server OPTIONS responses, set this option to "off".
    #Example:
    #icap_preview_enable off
    #
    #Default:
    # icap_preview_enable on

    #  TAG: icap_preview_size
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    The default size of preview data to be sent to the ICAP server.
    #    -1 means no preview. This value might be overwritten on a per server
    #    basis by OPTIONS requests.
    #
    #Default:
    # icap_preview_size -1

    #  TAG: icap_default_options_ttl
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    The default TTL value for ICAP OPTIONS responses that don't have
    #    an Options-TTL header.
    #
    #Default:
    # icap_default_options_ttl 60

    #  TAG: icap_persistent_connections    on|off
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    Whether or not Squid should use persistent connections to
    #    an ICAP server.
    #
    #Default:
    # icap_persistent_connections on

    #  TAG: icap_send_client_ip    on|off
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    This adds the header "X-Client-IP" to ICAP requests.
    #
    #Default:
    # icap_send_client_ip off

    #  TAG: icap_send_client_username    on|off
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    This sends authenticated HTTP client username (if available) to
    #    the ICAP service. The username value is encoded based on the
    #    icap_client_username_encode option and is sent using the header
    #    specified by the icap_client_username_header option.
    #
    #Default:
    # icap_send_client_username off

    #  TAG: icap_client_username_header
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    ICAP request header name to use for send_client_username.
    #
    #Default:
    # icap_client_username_header X-Client-Username

    #  TAG: icap_client_username_encode    on|off
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    Whether to base64 encode the authenticated client username.
    #
    #Default:
    # icap_client_username_encode off

    #  TAG: icap_service
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    Defines a single ICAP service
    #
    #    icap_service servicename vectoring_point bypass service_url
    #
    #    vectoring_point = reqmod_precache|reqmod_postcache|respmod_precache|respmod_postcache
    #        This specifies at which point of transaction processing the
    #        ICAP service should be activated. *_postcache vectoring points
    #        are not yet supported.
    #    bypass = 1|0
    #        If set to 1, the ICAP service is treated as optional. If the
    #        service cannot be reached or malfunctions, Squid will try to
    #        ignore any errors and process the message as if the service
    #        was not enabled. No all ICAP errors can be bypassed.
    #        If set to 0, the ICAP service is treated as essential and all
    #        ICAP errors will result in an error page returned to the
    #        HTTP client.
    #    service_url = icap://servername:port/service
    #
    #Example:
    #icap_service service_1 reqmod_precache 0 icap://icap1.mydomain.net:1344/reqmod
    #icap_service service_2 respmod_precache 0 icap://icap2.mydomain.net:1344/respmod
    #
    #Default:
    # none

    #  TAG: icap_class
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    Defines an ICAP service chain. Eventually, multiple services per
    #    vectoring point will be supported. For now, please specify a single
    #    service per class:
    #
    #    icap_class classname servicename
    #
    #Example:
    #icap_class class_1 service_1
    #icap class class_2 service_1
    #icap class class_3 service_3
    #
    #Default:
    # none

    #  TAG: icap_access
    # Note: This option is only available if Squid is rebuilt with the
    #       -DICAP_CLIENT define
    #
    #    Redirects a request through an ICAP service class, depending
    #    on given acls
    #
    #    icap_access classname allow|deny [!]aclname...
    #
    #    The icap_access statements are processed in the order they appear in
    #    this configuration file. If an access list matches, the processing stops.
    #    For an "allow" rule, the specified class is used for the request. A "deny"
    #    rule simply stops processing without using the class. You can also use the
    #    special classname "None".
    #
    #    For backward compatibility, it is also possible to use services
    #    directly here.
    #Example:
    #icap_access class_1 allow all
    #
    #Default:
    # none


    # DNS OPTIONS
    # -----------------------------------------------------------------------------

    #  TAG: check_hostnames
    #    For security and stability reasons Squid can check
    #    hostnames for Internet standard RFC compliance. If you want
    #    Squid to perform these checks turn this directive on.
    #
    #Default:
    # check_hostnames off

    #  TAG: allow_underscore
    #    Underscore characters is not strictly allowed in Internet hostnames
    #    but nevertheless used by many sites. Set this to off if you want
    #    Squid to be strict about the standard.
    #    This check is performed only when check_hostnames is set to on.
    #
    #Default:
    # allow_underscore on

    #  TAG: cache_dns_program
    #    Specify the location of the executable for dnslookup process.
    #
    #Default:
    # cache_dns_program /usr/local/squid3.0/libexec/dnsserver

    #  TAG: dns_children
    #    The number of processes spawn to service DNS name lookups.
    #    For heavily loaded caches on large servers, you should
    #    probably increase this value to at least 10.  The maximum
    #    is 32.  The default is 5.
    #
    #    You must have at least one dnsserver process.
    #
    #Default:
    # dns_children 5

    #  TAG: dns_retransmit_interval
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-internal-dns option
    #
    #    Initial retransmit interval for DNS queries. The interval is
    #    doubled each time all configured DNS servers have been tried.
    #
    #
    #Default:
    # dns_retransmit_interval 5 seconds

    #  TAG: dns_timeout
    # Note: This option is only available if Squid is rebuilt with the
    #       --enable-internal-dns option
    #
    #    DNS Query timeout. If no response is received to a DNS query
    #    within this time all DNS servers for the queried domain
    #    are assumed to be unavailable.
    #
    #Default:
    # dns_timeout 2 minutes

    #  TAG: dns_defnames    on|off
    #    Normally the RES_DEFNAMES resolver option is disabled
    #    (see res_init(3)).  This prevents caches in a hierarchy
    #    from interpreting single-component hostnames locally.  To allow
    #    Squid to handle single-component names, enable this option.
    #
    #Default:
    # dns_defnames off

    #  TAG: dns_nameservers
    #    Use this if you want to specify a list of DNS name servers
    #    (IP addresses) to use instead of those given in your
    #    /etc/resolv.conf file.
    #    On Windows platforms, if no value is specified here or in
    #    the /etc/resolv.conf file, the list of DNS name servers are
    #    taken from the Windows registry, both static and dynamic DHCP
    #    configurations are supported.
    #
    #    Example: dns_nameservers 10.0.0.1 192.172.0.4
    #
    #Default:
    # none

    #  TAG: hosts_file
    #    Location of the host-local IP name-address associations
    #    database. Most Operating Systems have such a file on different
    #    default locations:
    #    - Un*X & Linux:    /etc/hosts
    #    - Windows NT/2000: %SystemRoot%system32driversetchosts
    #               (%SystemRoot% value install default is c:winnt)
    #    - Windows XP/2003: %SystemRoot%system32driversetchosts
    #               (%SystemRoot% value install default is c:windows)
    #    - Windows 9x/Me:   %windir%hosts
    #               (%windir% value is usually c:windows)
    #    - Cygwin:       /etc/hosts
    #
    #    The file contains newline-separated definitions, in the
    #    form ip_address_in_dotted_form name [name ...] names are
    #    whitespace-separated. Lines beginning with an hash (#)
    #    character are comments.
    #
    #    The file is checked at startup and upon configuration.
    #    If set to 'none', it won't be checked.
    #    If append_domain is used, that domain will be added to
    #    domain-local (i.e. not containing any dot character) host
    #    definitions.
    #
    #Default:
    # hosts_file /etc/hosts

    #  TAG: dns_testnames
    #    The DNS tests exit as soon as the first site is successfully looked up
    #
    #    This test can be disabled with the -D command line option.
    #
    #Default:
    # dns_testnames netscape.com internic.net nlanr.net microsoft.com

    #  TAG: append_domain
    #    Appends local domain name to hostnames without any dots in
    #    them.  append_domain must begin with a period.
    #
    #    Be warned there are now Internet names with no dots in
    #    them using only top-domain names, so setting this may
    #    cause some Internet sites to become unavailable.
    #
    #Example:
    # append_domain .yourdomain.com
    #
    #Default:
    # none

    #  TAG: ignore_unknown_nameservers
    #    By default Squid checks that DNS responses are received
    #    from the same IP addresses they are sent to.  If they
    #    don't match, Squid ignores the response and writes a warning
    #    message to cache.log.  You can allow responses from unknown
    #    nameservers by setting this option to 'off'.
    #
    #Default:
    # ignore_unknown_nameservers on

    #  TAG: ipcache_size    (number of entries)
    #  TAG: ipcache_low    (percent)
    #  TAG: ipcache_high    (percent)
    #    The size, low-, and high-water marks for the IP cache.
    #
    #Default:
    # ipcache_size 1024
    # ipcache_low 90
    # ipcache_high 95

    #  TAG: fqdncache_size    (number of entries)
    #    Maximum number of FQDN cache entries.
    #
    #Default:
    # fqdncache_size 1024


    # MISCELLANEOUS
    # -----------------------------------------------------------------------------

    #  TAG: memory_pools    on|off
    #    If set, Squid will keep pools of allocated (but unused) memory
    #    available for future use.  If memory is a premium on your
    #    system and you believe your malloc library outperforms Squid
    #    routines, disable this.
    #
    #Default:
    # memory_pools on

    #  TAG: memory_pools_limit    (bytes)
    #    Used only with memory_pools on:
    #    memory_pools_limit 50 MB
    #
    #    If set to a non-zero value, Squid will keep at most the specified
    #    limit of allocated (but unused) memory in memory pools. All free()
    #    requests that exceed this limit will be handled by your malloc
    #    library. Squid does not pre-allocate any memory, just safe-keeps
    #    objects that otherwise would be free()d. Thus, it is safe to set
    #    memory_pools_limit to a reasonably high value even if your
    #    configuration will use less memory.
    #
    #    If set to zero, Squid will keep all memory it can. That is, there
    #    will be no limit on the total amount of memory used for safe-keeping.
    #
    #    To disable memory allocation optimization, do not set
    #    memory_pools_limit to 0. Set memory_pools to "off" instead.
    #
    #    An overhead for maintaining memory pools is not taken into account
    #    when the limit is checked. This overhead is close to four bytes per
    #    object kept. However, pools may actually _save_ memory because of
    #    reduced memory thrashing in your malloc library.
    #
    #Default:
    # memory_pools_limit 5 MB

    #  TAG: forwarded_for    on|off
    #    If set, Squid will include your system's IP address or name
    #    in the HTTP requests it forwards.  By default it looks like
    #    this:
    #
    #        X-Forwarded-For: 192.1.2.3
    #
    #    If you disable this, it will appear as
    #
    #        X-Forwarded-For: unknown
    #
    #Default:
    # forwarded_for on

    #  TAG: cachemgr_passwd
    #    Specify passwords for cachemgr operations.
    #
    #    Usage: cachemgr_passwd password action action ...
    #
    #    Some valid actions are (see cache manager menu for a full list):
    #        5min
    #        60min
    #        asndb
    #        authenticator
    #        cbdata
    #        client_list
    #        comm_incoming
    #        config *
    #        counters
    #        delay
    #        digest_stats
    #        dns
    #        events
    #        filedescriptors
    #        fqdncache
    #        histograms
    #        http_headers
    #        info
    #        io
    #        ipcache
    #        mem
    #        menu
    #        netdb
    #        non_peers
    #        objects
    #        offline_toggle *
    #        pconn
    #        peer_select
    #        reconfigure *
    #        redirector
    #        refresh
    #        server_list
    #        shutdown *
    #        store_digest
    #        storedir
    #        utilization
    #        via_headers
    #        vm_objects
    #
    #    * Indicates actions which will not be performed without a
    #      valid password, others can be performed if not listed here.
    #
    #    To disable an action, set the password to "disable".
    #    To allow performing an action without a password, set the
    #    password to "none".
    #
    #    Use the keyword "all" to set the same password for all actions.
    #
    #Example:
    # cachemgr_passwd secret shutdown
    # cachemgr_passwd lesssssssecret info stats/objects
    # cachemgr_passwd disable all
    #
    #Default:
    # none

    #  TAG: client_db    on|off
    #    If you want to disable collecting per-client statistics,
    #    turn off client_db here.
    #
    #Default:
    # client_db on

    #  TAG: refresh_all_ims    on|off
    #    When you enable this option, squid will always check
    #    the origin server for an update when a client sends an
    #    If-Modified-Since request.  Many browsers use IMS
    #    requests when the user requests a reload, and this
    #    ensures those clients receive the latest version.
    #
    #    By default (off), squid may return a Not Modified response
    #    based on the age of the cached version.
    #
    #Default:
    # refresh_all_ims off

    #  TAG: reload_into_ims    on|off
    #    When you enable this option, client no-cache or ``reload''
    #    requests will be changed to If-Modified-Since requests.
    #    Doing this VIOLATES the HTTP standard.  Enabling this
    #    feature could make you liable for problems which it
    #    causes.
    #
    #    see also refresh_pattern for a more selective approach.
    #
    #Default:
    # reload_into_ims off

    #  TAG: maximum_single_addr_tries
    #    This sets the maximum number of connection attempts for a
    #    host that only has one address (for multiple-address hosts,
    #    each address is tried once).
    #
    #    The default value is one attempt, the (not recommended)
    #    maximum is 255 tries.  A warning message will be generated
    #    if it is set to a value greater than ten.
    #
    #    Note: This is in addition to the request re-forwarding which
    #    takes place if Squid fails to get a satisfying response.
    #
    #Default:
    # maximum_single_addr_tries 1

    #  TAG: retry_on_error
    #    If set to on Squid will automatically retry requests when
    #    receiving an error response. This is mainly useful if you
    #    are in a complex cache hierarchy to work around access
    #    control errors.
    #
    #Default:
    # retry_on_error off

    #  TAG: as_whois_server
    #    WHOIS server to query for AS numbers.  NOTE: AS numbers are
    #    queried only when Squid starts up, not for every request.
    #
    #Default:
    # as_whois_server whois.ra.net
    # as_whois_server whois.ra.net

    #  TAG: offline_mode
    #    Enable this option and Squid will never try to validate cached
    #    objects.
    #
    #Default:
    # offline_mode off

    #  TAG: uri_whitespace
    #    What to do with requests that have whitespace characters in the
    #    URI.  Options:
    #
    #    strip:  The whitespace characters are stripped out of the URL.
    #        This is the behavior recommended by RFC2396.
    #    deny:   The request is denied.  The user receives an "Invalid
    #        Request" message.
    #    allow:  The request is allowed and the URI is not changed.  The
    #        whitespace characters remain in the URI.  Note the
    #        whitespace is passed to redirector processes if they
    #        are in use.
    #    encode:    The request is allowed and the whitespace characters are
    #        encoded according to RFC1738.  This could be considered
    #        a violation of the HTTP/1.1
    #        RFC because proxies are not allowed to rewrite URI's.
    #    chop:    The request is allowed and the URI is chopped at the
    #        first whitespace.  This might also be considered a
    #        violation.
    #
    #Default:
    # uri_whitespace strip

    #  TAG: coredump_dir
    #    By default Squid leaves core files in the directory from where
    #    it was started. If you set 'coredump_dir' to a directory
    #    that exists, Squid will chdir() to that directory at startup
    #    and coredump files will be left there.
    #
    #Default:
    # coredump_dir none
    #
    # Leave coredumps in the first cache dir
    coredump_dir /usr/local/squid3.0/var/cache

    #  TAG: chroot
    #    Specifies a directory where Squid should do a chroot() while
    #    initializing.  This also causes Squid to fully drop root
    #    privileges after initializing.  This means, for example, if you
    #    use a HTTP port less than 1024 and try to reconfigure, you may
    #    get an error saying that Squid can not open the port.
    #
    #Default:
    # none

    #  TAG: balance_on_multiple_ip
    #    Some load balancing servers based on round robin DNS have been
    #    found not to preserve user session state across requests
    #    to different IP addresses.
    #
    #    By default Squid rotates IP's per request. By disabling
    #    this directive only connection failure triggers rotation.
    #
    #Default:
    # balance_on_multiple_ip on

    #  TAG: pipeline_prefetch
    #    To boost the performance of pipelined requests to closer
    #    match that of a non-proxied environment Squid can try to fetch
    #    up to two requests in parallel from a pipeline.
    #
    #    Defaults to off for bandwidth management and access logging
    #    reasons.
    #
    #Default:
    # pipeline_prefetch off

    #  TAG: high_response_time_warning    (msec)
    #    If the one-minute median response time exceeds this value,
    #    Squid prints a WARNING with debug level 0 to get the
    #    administrators attention.  The value is in milliseconds.
    #
    #Default:
    # high_response_time_warning 0

    #  TAG: high_page_fault_warning
    #    If the one-minute average page fault rate exceeds this
    #    value, Squid prints a WARNING with debug level 0 to get
    #    the administrators attention.  The value is in page faults
    #    per second.
    #
    #Default:
    # high_page_fault_warning 0

    #  TAG: high_memory_warning
    #    If the memory usage (as determined by mallinfo) exceeds
    #    this amount, Squid prints a WARNING with debug level 0 to get
    #    the administrators attention.
    #
    #Default:
    # high_memory_warning 0 KB

    #  TAG: sleep_after_fork    (microseconds)
    #    When this is set to a non-zero value, the main Squid process
    #    sleeps the specified number of microseconds after a fork()
    #    system call. This sleep may help the situation where your
    #    system reports fork() failures due to lack of (virtual)
    #    memory. Note, however, if you have a lot of child
    #    processes, these sleep delays will add up and your
    #    Squid will not service requests for some amount of time
    #    until all the child processes have been started.
    #    On Windows value less then 1000 (1 milliseconds) are
    #    rounded to 1000.
    #
    #Default:
    # sleep_after_fork 0

    #  TAG: windows_ipaddrchangemonitor    on|off
    #    On Windows Squid by default will monitor IP address changes and will
    #    reconfigure itself after any detected event. This is very useful for
    #    proxies connected to internet with dial-up interfaces.
    #    In some cases (a Proxy server acting as VPN gateway is one) it could be
    #    desiderable to disable this behaviour setting this to 'off'.
    #    Note: after changing this, Squid service must be restarted.
    #
    #Default:
    # windows_ipaddrchangemonitor on

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  • 原文地址:https://www.cnblogs.com/yangshun2005/p/6149431.html
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