C# IP地址存取控制

            string ipLimit = "192.168.152.x,192.168.153.x,192.168.154.x,192.168.155.x,192.168.156.x,192.168.157.x,192.168.158.x,192.168.159.x,192.168.x.x";            string[] arrSeperators = { "," };            string[] ipList = ipLimit.Split(arrSeperators, StringSplitOptions.RemoveEmptyEntries);            if (!CheckIPLimit(ipList, GetRemoteIP()))            {                   return“不可以訪問”;            }

獲得請求的IP地址函數GetRemoteIP()：

        private string GetRemoteIP()        {            string ip = "";            if (Context.Request.ServerVariables["HTTP_VIA"] != null) // 伺服器， using proxy            {                //得到真實的用戶端地址                ip = Context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString(); // Return real client IP.            }            else//如果沒有使用Proxy 伺服器或者得不到用戶端的ip not using proxy or can't get the Client IP            {                // 得到服務端的地址                ip = Context.Request.ServerVariables["REMOTE_ADDR"].ToString(); //While it can't get the Client IP, it will return proxy IP.            }            return ip;        }    }

下面的函數將 string[] ipList與請求IP一一比較（分段比較）：

   private bool CheckIPLimit(string[] ipList, string remoteIP)        {            foreach (string ip in ipList)            {                if (CompareIP(ip, remoteIP))                {                    return true;                }            }            return false;        }        private bool CompareIP(string oldIP, string newIP)        {            string[] arrSeperators = { "." };            string[] oldIPList = oldIP.Split(arrSeperators, StringSplitOptions.RemoveEmptyEntries);            string[] newIPList = newIP.Split(arrSeperators, StringSplitOptions.RemoveEmptyEntries);            if (oldIPList.Length != newIPList.Length)            {                return false;            }            for (int i = 0; i < oldIPList.Length; i++)            {                if (oldIPList[i] != checkedIP & oldIPList[i] != newIPList[i])//截取的ip是‘x’則是true                {                    return false;                }            }            return true;        }