MailKit.Net.Smtp.SmtpClient.SendEhlo C# (CSharp) Method

		SmtpResponse SendEhlo (bool ehlo, CancellationToken cancellationToken)
		{
			string command = ehlo ? "EHLO " : "HELO ";

#if !NETFX_CORE
			string domain = null;
			IPAddress ip = null;

			if (!string.IsNullOrEmpty (LocalDomain)) {
				if (!IPAddress.TryParse (LocalDomain, out ip))
					domain = LocalDomain;
			} else if (Stream.Socket != null) {
				var ipEndPoint = Stream.Socket.LocalEndPoint as IPEndPoint;

				if (ipEndPoint == null)
					domain = ((DnsEndPoint) Stream.Socket.LocalEndPoint).Host;
				else
					ip = ipEndPoint.Address;
			} else {
				domain = "[127.0.0.1]";
			}

			if (ip != null) {
				if (ip.AddressFamily == AddressFamily.InterNetworkV6)
					domain = "[IPv6:" + ip + "]";
				else
					domain = "[" + ip + "]";
			}

			command += domain;
#else
			if (!string.IsNullOrEmpty (LocalDomain))
				command += LocalDomain;
			else if (!string.IsNullOrEmpty (Stream.Socket.Information.LocalAddress.CanonicalName))
				command += Stream.Socket.Information.LocalAddress.CanonicalName;
			else
				command += "localhost.localdomain";
#endif

			return SendCommand (command, cancellationToken);
		}