telnet starttls command
telnet send command example
manual smtp transaction
telnet smtp.office365.com 587 authtest smtp command line linux
smtp commands
smtp test tool
telnet smtp auth

Sep 17, 2018 -Mar 10, 2020 - Jump to How to test SMTP server with a manual telnet session? - From command line/shell in any OS that has Telnet feature installed: telnet mail.example.net 25 #this is your mail server ehlo hostname.local #this is your Sep 28, 2017 - Apr 1, 2020 - It can confirm whether the Exchange server is processing email correctly and is really the manual way of entering the commands that SMTP servers do when Feb 7, 2020 - May 28, 2020 - Feb 7, 2020 -