My Geek Finds

Nothing spectacular here, but at times you may need to manually test an SMTP connection, so here is how (the mail server responses are italic):

telnet mailhost.domain.com 25

220 mailhost.domain.com ESMTP MAILHOST

helo yourhost.yourdomain.com

250 mailhost.domain.com Hello yourhost.yourdomain.com [yourip], pleased to meet you

mail from: youremail@yourdomain.com

250 2.1.0 Sender ok

rcpt to: recipientemail@recipientdomain.com

250 2.1.5 Recipient ok

data

354 Enter mail, end with “.” on a line by itself

Subject: Test Message

Test Message
.

250 2.0.0 Message accepted for delivery

quit

The responses may vary a bit depending on the SMTP server but that is basically it.

Details on the SMTP server response codes can be found in rfc2821 check sections 4.2.2 and 4.2.3