1、HttpContext.Current.Request.UserHostAddress;
2、HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
3、string strHostName = System.Net.Dns.GetHostName();
string clientIPAddress = System.Net.Dns.GetHostAddresses(strHostName).GetValue(0).ToString();
4、HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
5、private