/// <summary>     /// C#获取客户端真实IP地址     /// </summary>     /// <returns></returns>     public static string GetIP()     {         string ip = HttpContext.Current.Request.ServerVariables["http_x_forwarded_for"];         if (UserCheck.IsNull(ip)) ip = HttpContext.Current.Request.ServerVariables["remote_addr"];         return ip;     }

 /// <summary>     /// C#将IP地址转为长整形     /// </summary>     /// <param name="ip"></param>     /// <returns></returns>     public static long IpToNumber(string ip)     {         string[] arr = ip.Split('.');         return 256 * 256 * 256 * long.Parse(arr[0]) + 256 * 256 * long.Parse(arr[1]) + 256 * long.Parse(arr[2]) + long.Parse(arr[3]);     }     /// <summary>     /// C#判断IP地址是否为私有/内网ip地址     /// </summary>     /// <param name="ip"></param>     /// <returns></returns>     public static bool IsPrivateIp(string ip)     {         long ABegin = IpToNumber("10.0.0.0"), AEnd = IpToNumber("10.255.255.255"),//A类私有IP地址          BBegin = IpToNumber("172.16.0.0"), BEnd = IpToNumber("172.31.255.255"),//'B类私有IP地址          CBegin = IpToNumber("192.168.0.0"), CEnd = IpToNumber("192.168.255.255"),//'C类私有IP地址          IpNum = IpToNumber(ip);         return (ABegin <= IpNum && IpNum <= AEnd) || (BBegin <= IpNum && IpNum <= BEnd) || (CBegin <= IpNum && IpNum <= CEnd);     }     /// <summary>     /// C#获取真实IP地址     /// </summary>     /// <returns></returns>     public static string GetIP()     {         string ip = HttpContext.Current.Request.ServerVariables["http_x_forwarded_for"];         if (UserCheck.IsNull(ip)) ip = HttpContext.Current.Request.ServerVariables["remote_addr"];         else//代理ip地址有内容，判断是否符合ipv4地址或者是否为内网地址         {             ip = ip.Trim().Replace(" ", "");             if (!Regex.IsMatch(ip, @"^\d+(\.\d+){3}$") || IsPrivateIp(ip))                 ip = HttpContext.Current.Request.ServerVariables["remote_addr"];//不符合规则或者内网/私有地址使用remote_addr代替         }         return ip;     }