话不多说，请看代码：
string requestClientIpAddress = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]; if (string.IsNullOrEmpty(requestClientIpAddress)) requestClientIpAddress = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"]; if (string.IsNullOrEmpty(requestClientIpAddress)) requestClientIpAddress = HttpContext.Current.Request.UserHostAddress;
经过测试 存在负载均衡的时候 ,HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] 取出的是真实的客户端 IP地址 ,而HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"] 和 HttpContext.Current.Request.UserHostAddress 取出的是被分配的保留地址