How to test your mail server – imap, imaps, pop3, pop3s, smtp, smtps – using telnet

 telnet mx.example.com smtp

 telnet mx.example.com smtps

 telnet mx.example.com imap

 telnet mx.example.com imaps

 telnet mx.example.com pop3

 telnet mx.example.com pop3s

You should see the following message when testing a server.

telnet:Connected to mx.example.com.