判断IP是否是外网IP、内网IP

        /// <summary>
        /// 是否内外IP
        /// </summary>
        /// <param name="ipAddress"></param>
        /// <returns></returns>
        public static bool IsInternalIP(string ipAddress)
        {
            bool isInnerIp = false;
            long ipNum = GetIpNum(ipAddress);
            /*------------------------------------------
                私有IP：A类 10.0.0.0-10.255.255.255
                       B类 172.16.0.0-172.31.255.255
                       C类 192.168.0.0-192.168.255.255
                当然，还有127这个网段是环回地址
            ------------------------------------------*/
            long aBegin = GetIpNum("10.0.0.0");
            long aEnd = GetIpNum("10.255.255.255");
            long bBegin = GetIpNum("172.16.0.0");
            long bEnd = GetIpNum("172.31.255.255");
            long cBegin = GetIpNum("192.168.0.0");
            long cEnd = GetIpNum("192.168.255.255");
            isInnerIp = IsInner(ipNum, aBegin, aEnd) || IsInner(ipNum, bBegin, bEnd) || IsInner(ipNum, cBegin, cEnd) || ipAddress.Equals("127.0.0.1");
            return isInnerIp;
        }

        /// <summary>
        /// 把IP地址转换为Long型数字
        /// </summary>
        /// <param name="ipAddress">IP地址字符串</param>
        /// <returns></returns>
        private static long GetIpNum(string ipAddress)
        {
            string[] ip = ipAddress.Split('.');
            long a = int.Parse(ip[0]);
            long b = int.Parse(ip[1]);
            long c = int.Parse(ip[2]);
            long d = int.Parse(ip[3]);

            long ipNum = a * 256 * 256 * 256 + b * 256 * 256 + c * 256 + d;
            return ipNum;
        }

        private static bool IsInner(long userIp, long begin, long end)
        {
            return (userIp >= begin) && (userIp <= end);
        }