We have one client using secured email service, which requires TSL excrypted messaging, but after enabling TLS for this domain, the TLSSTART command is still unrecognized.. Of course the SMG server at this point don't even know about the destination domain, and it's settings. So does the Messaging Gateway support TLS handshaking or not, and what might be the problem here?
telnet qntsrv9.qnet.fi 25
Connected to qntsrv9.qnet.fi.
Escape character is '^]'.
220 qntsrv9.qnet.fi ESMTP Q-Net Spamcontrol ehlo turvaposti.fi 250-qntsrv9.qnet.fi says EHLO to 220.127.116.11:35317 250-8BITMIME 250-PIPELINING 250-SIZE 110000000
500 5.5.2 unrecognized command
Actually found the solution, https://support.symantec.com/us/en/article.howto58876.html, and now SMG responds with a proper STARTTLS response: