Kerberos客户端常用命令包括 kinit, klist, kdestroy, and kpasswd，用户使用这些命令管理自己的 ticket。
此外，每台运行Kerberos的机器应该都配置/etc/krb5.conf，At a minimum, it should define a default_realm setting in [libdefaults]. If you are not using DNS SRV records, it must also contain a [realms] section containing information for your realm’s KDCs.
Ticket 管理
Kerberos Ticket的若干属性：
- forwardable 简单来讲，KDC可以基于该类型TGT发放新的TGT，即使 network address不同。这样不需要再次输入密码。
- proxiable 类似于forwardable，但是不同的是只允许service继承client的认证
- proxy
- postdated
- Renewable 用户不需要重新输入密码就可以获得新的 session key. 但是这种TGT有过期时间。
- invalid
- hardware authentication 申请使用硬件的Ticket认证
- okay as delegate ticket指定的服务器可以用作delegate determined by the policy of that realm
- anonymous ticket is one in which the named principal is a generic principal for that realm; it does not actually specify the individual that will be using the ticket. This ticket is meant only to securely distribute a session key.
用 kinit 获得Ticket
如果你的登录系统集成了Kerberos v5，那么登录时自动获得kerberos ticket. 否则，必须显示获取，比如用 kinit。类似，如果 ticket过期了，kinit可以申请新的ticket.
By default, kinit假设你想要默认realm里与自己名字相同的principal的ticket。
shell% kinit Password for jennifer@ATHENA.MIT.EDU: <-- [Type jennifer's password here.] shell%
如果想要申请 forwardable ticket，可以
shell% kinit -f Password for jennifer@ATHENA.MIT.EDU: <-- [Type your password here.] shell% shell% kinit -f -l 3h david@EXAMPLE.COM Password for david@EXAMPLE.COM: <-- [Type david's password here.] shell%
用 klist 查看 ticket
当你第一次获得 ticket, 那么只能是TGT，看起来如下：
shell% klist Ticket cache: /tmp/krb5cc_ttypa Default principal: jennifer@ATHENA.MIT.EDU Valid starting Expires Service principal 06/07/04 19:49:21 06/08/04 05:49:19 krbtgt/ATHENA.MIT.EDU@ATHENA.MIT.EDU shell%
如果连接到其他机器上，比如：daffodil.mit.edu，但是在同一个realm，klist会得到
shell% klist Ticket cache: /tmp/krb5cc_ttypa Default principal: jennifer@ATHENA.MIT.EDU Valid starting Expires Service principal 06/07/04 19:49:21 06/08/04 05:49:19 krbtgt/ATHENA.MIT.EDU@ATHENA.MIT.EDU 06/07/04 20:22:30 06/08/04 05:49:19 host/daffodil.mit.edu@ATHENA.MIT.EDU shell%
当jennifer用ssh程序登陆主机daffodil.mit.edu，ssh程序将jennifer的TGT给KDC，并请求主机ticket，这样jennifer不用再输入密码。
klist有各种flag，具体可以通过 man klist 查看。
用 kdestory 销毁ticket.
由于ticket可能被偷走，这样离开机器的时候可以顺便销毁ticket.
shell% kdestroy
shell%
其他客户端命令
- kdestroy: kdestroy utility destroys the user’s active Kerberos authorization tickets by overwriting and deleting the credentials cache that contains them
- kinit: kinit obtains and caches an initial ticket-granting ticket(TGT) for principal
- klist: klist lists the Kerberos principal and Kerberos tickets held in a credentials cache, or the keys held in a keytab file.
- kpasswd: kpasswd command is used to change a Kerberos principal’s password
- krb5-config
- ksu
- kswitch
- kvno
- sclient