/// <summary>
    /// C#獲取客戶端真實(shí)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#將IP地址轉(zhuǎn)為長整形
    /// </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#判斷IP地址是否為私有/內(nèi)網(wǎng)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類私有IP地址
         BBegin = IpToNumber("172.16.0.0"), BEnd = IpToNumber("172.31.255.255"),//'B類私有IP地址
         CBegin = IpToNumber("192.168.0.0"), CEnd = IpToNumber("192.168.255.255"),//'C類私有IP地址
         IpNum = IpToNumber(ip);
        return (ABegin <= IpNum && IpNum <= AEnd) || (BBegin <= IpNum && IpNum <= BEnd) || (CBegin <= IpNum && IpNum <= CEnd);
    }
    /// <summary>
    /// C#獲取真實(shí)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地址有內(nèi)容，判斷是否符合ipv4地址或者是否為內(nèi)網(wǎng)地址
        {
            ip = ip.Trim().Replace(" ", "");
            if (!Regex.IsMatch(ip, @"^\d+(\.\d+){3}$") || IsPrivateIp(ip))
                ip = HttpContext.Current.Request.ServerVariables["remote_addr"];//不符合規(guī)則或者內(nèi)網(wǎng)/私有地址使用remote_addr代替
        }
        return ip;
    }