isLocalhost

        public static bool isLocalhost(string sHostAndPort)
        {
            string str;
            int iPort = 0;
            CrackHostAndPort(sHostAndPort, out str, ref iPort);
            if ((!string.Equals(str, "localhost", StringComparison.OrdinalIgnoreCase) && !string.Equals(str, "localhost.", StringComparison.OrdinalIgnoreCase)) && !string.Equals(str, "127.0.0.1", StringComparison.OrdinalIgnoreCase))
            {
                return string.Equals(str, "::1", StringComparison.OrdinalIgnoreCase);
            }
            return true;
        }