Telnet to mail server
Lets first create a variable, so you can just copy/paste the code.
Replace mail.example.net with your telnet destination domain name.
export REMOTE_SRV=mail.example.net telnet start $ telnet $REMOTE_SRV 25 $ telnet $REMOTE_SRV 143 c = Client, this is what you will enter s = Server, response we receive. c: telnet $REMOTE_SRV 587 s: Trying 107.189.21.115... s: Connected to mail.example.net. s: Escape character is '^]'. s: 220 mail.example.net ESMTP Citadel server ready.