Sep 19, 2018

How to verify email server supports TLS connections

You can verify by connecting and issuing an EHLO command from the command line interface. The resultant “250 STARTTLS” confirms the endpoint accepts TLS connection requests.

telnet smtp.i88.ca 587

Connected to smtp.i88.ca.
Escape character is '^]'.

220 pepipost.com

ehlo i88.ca
250-PIPELINING

250-SIZE 20783082

250-VRFY

250-ETRN

250-STARTTLS