獲取遠程客戶端的真實IP地址

    private string GetClientIP()
    {
        string ipaddress = string.Empty;
        if (Request.ServerVariables["remote_addr"] != null)//發出請求的遠程主機的ip地址
        {
            ipaddress = Request.ServerVariables["remote_addr"];
        }
        else if (Request.ServerVariables["http_via"] != null)//判斷是否設置代理，若使用了代理
        {
            if (Request.ServerVariables["http_x_forwarded_for"] != null)//獲取代理服務器的ip
            {
                ipaddress = Request.ServerVariables["http_x_forwarded_for"];
            }
            else
            {
                ipaddress = Request.UserHostAddress;
            }
        }
        else
        {
            ipaddress = Request.UserHostAddress;
        }
        return ipaddress;
    }