SMTP Cheat Sheet

From the “my external memory dept”:

One of the simplest way to debug SMTP problems is to talk directly to the SMTP server using a shell (Telnet):

Frodo:~ jcf$ telnet smtp.domain.ch 25
Trying xxx.xxx.xxx.xxx...
Connected to smtp.domain.ch.
Escape character is '^]'.
220 smtp.domain.ch ESMTP ready.
MAIL FROM:name@domain.ch 
250 OK
RCPT TO:joe@doe.com
250 Accepted 
DATA
354 Enter message, ending with "." on a line by itself

and then the message you want to send (including the headers)