telnet - using telnet to test email server or send email (smtp pop 25) using telnet

telnet is a Swiss army knife for troubleshooting layer 7 application problem, especially useful on smtp & pop3 protocol.

Scenario 1 :
to test is our domain is being block by recipient domain, using telnet on our email server to send email on recipient email server.


Scenario 2 :
a quick test on error occurs sending email, using email client, such as thunderbird, apple mail, opera mail & others, using telnet.


Sample of using telnet to send email :

telnet smtp.domain.my 25

helo local-host-name

mail from:sender@domain.com

rcpt to:recipient@domain.com

data

Type the content upon a new line after the previous command. End the "data" session by only put a dot (.)

.

at the newline

quit

Voilla !!!