ASP.NET 获取客户端IP （无视代理）

  public static string ClientIP()
    {
        string result = String.Empty;

        result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
        if (result != null && result != String.Empty)
        {
            //可能有代理 
            if (result.IndexOf(".") == -1)     //没有“.”肯定是非IPv4格式 
                result = null;
            else
            {
                if (result.IndexOf(",") != -1)
                {
                    //有“,”，估计多个代理。取第一个不是内网的IP。 
                    result = result.Replace(" ", "").Replace("'", "");
                    string[] temparyip = result.Split(",;".ToCharArray());
                    for (int i = 0; i < temparyip.Length; i++)
                    {
                        if (IsIPAddress(temparyip[i]) && temparyip[i].Substring(0, 3) != "10." && temparyip[i].Substring(0, 7) != "192.168" && temparyip[i].Substring(0, 7) != "172.16.")
                        {
                            return temparyip[i];     //找到不是内网的地址 
                        }
                    }
                }
                else if (IsIPAddress(result)) //代理即是IP格式 
                    return result;
                else
                    result = null;     //代理中的内容 非IP，取IP 
            }

        }

        string IpAddress = (HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != null && HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] != String.Empty) ? HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] : HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

        if (null == result || result == String.Empty)
            result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

        if (result == null || result == String.Empty)
            result = HttpContext.Current.Request.UserHostAddress;

        return result;
    }

#region bool IsIPAddress(str1) 判断是否是IP格式
    /**/
    /// <summary>
    /// 判断是否是IP地址格式 0.0.0.0
    /// </summary>
    /// <param name="str1">待判断的IP地址</param>
    /// <returns>true or false</returns>
    public static bool IsIPAddress(string str1)
    {
        if (str1 == null || str1 == string.Empty || str1.Length < 7 || str1.Length > 15) return false;

        string regformat = @"^\d{1,3}[\.]\d{1,3}[\.]\d{1,3}[\.]\d{1,3}$";

        Regex regex = new Regex(regformat, RegexOptions.IgnoreCase);
        return regex.IsMatch(str1);
    }
    #endregion