獲取客戶端IP

 public static string GetWebClientIp()
        {

            string userIP = "未獲取用戶IP";

            try
            {
                if (System.Web.HttpContext.Current == null
                    || System.Web.HttpContext.Current.Request == null
                    || System.Web.HttpContext.Current.Request.ServerVariables == null)
                    return "";

                string CustomerIP = "";

                //CDN加速後取到的IP simone 090805
                CustomerIP = System.Web.HttpContext.Current.Request.Headers["Cdn-Src-Ip"];
                if (!string.IsNullOrEmpty(CustomerIP))
                {
                    return CustomerIP;
                }

                CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];


                if (!String.IsNullOrEmpty(CustomerIP))
                    return CustomerIP;

                if (System.Web.HttpContext.Current.Request.ServerVariables["HTTP_VIA"] != null)
                {
                    CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
                    if (CustomerIP == null)
                        CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
                }
                else
                {
                    CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

                }

                if (string.Compare(CustomerIP, "unknown", true) == 0)
                    return System.Web.HttpContext.Current.Request.UserHostAddress;
                return CustomerIP;
            }
            catch
            {

            }

            return userIP;

        }