在有代理的情况下，因为要代替客户端去访问服务器，所以，当请求包经过反向代理后，在代理服务器这里这个IP数据包的IP包头做了修改，最终后端WEB服务器得到的数据包的头部源IP地址是代理服务器的IP地址。这样一来，后端服务器的程序就无法获取用户的真实ip。
nginx有代理的情况:
在nginx中配置中加入
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Real-Port $remote_port;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
Apache有代理的情况：
vi /usr/local/apache/conf/httpd.conf
Include conf/extra/httpd-remoteip.conf
vi /usr/local/apache/conf/extra/httpd-remoteip.conf
LoadModule remoteip_module modules/mod_remoteip.so
RemoteIPHeader X-Forwarded-For
RemoteIPInternalProxy 127.0.0.1
代码 示例
string GetClientIp(CgiInput* poInput)
{
string client_ip = "";
string strClientIPList;
GetHttpHeader("X-Forwarded-For", strClientIPList);
if (strClientIPList.empty())
{
GetHttpHeader("X-Real-IP", strClientIPList);
}
if (!strClientIPList.empty())
{
size_t iPos = strClientIPList.find( "," );
if( iPos != std::string::npos )
{
client_ip = strClientIPList.substr( iPos );
}
else
{
client_ip = strClientIPList;
}
}
if (client_ip.empty())
{
GetHttpHeader("PROXY_FORWARDED_FOR", strClientIPList);
// 做下兼容
if(strClientIPList.empty())
{
client_ip = getRemoteAddr();
}
else
{
size_t iPos = strClientIPList.find( "," );
if( iPos != std::string::npos )
{
client_ip = strClientIPList.substr( iPos );
}
else
{
client_ip = strClientIPList;
}
}
}
if(!MMPayCommFunc::IsIp(client_ip))
client_ip = getRemoteAddr();
return client_ip;
}