string VisitorIP = "";
           string VisitorIPV6 = ""; 
           var request = filterContext.RequestContext.HttpContext.Request;
            if (request.ServerVariables["HTTP_VIA"] != null) // 伺服器， using proxy
            {
                //得到真實的客戶端地址
                VisitorIP = request.ServerVariables["
 
HTTP_X_FORWARDED_FOR"].ToString(); // Return real client IP.
            }
            else//如果沒有使用代理伺服器或者得不到客戶端的ip not using proxy or can't get the Client IP
            {
                // 得到服務端的地址
                var ip = request.ServerVariables["REMOTE_ADDR"].ToString(); //While it can't get the Client IP, it will return proxy IP.
 

                if (ip.Equals("::1"))//::-1是ipV6地址，實際上就是本機的意思
                {
                    foreach (IPAddress _IPAddress in Dns.GetHostEntry(Dns.GetHostName()).AddressList)
                    {
                        //InterNetwork ipv4地址
                        if (_IPAddress.AddressFamily.ToString() == "
 
InterNetwork")
                        {
                          VisitorIP = _IPAddress.ToString();
                        }
                        //InterNetworkV6 ipv6地址
                        if (_IPAddress.AddressFamily.ToString() == "InterNetworkV6")
                         {
                            VisitorIPV6 = _IPAddress.ToString();
                         }         
                    }
                }