18 Feb
Testing SMTP With Telnet
I love the internet application protocols like HTTP and SMTP, because they are easily testable with telnet and simple ascii input. Like for example when I needed to test, if a postfix installation of mine was able to relay from a host I had configured it to allow from. I just logged in to the host it needed to be able to relay from, and did this:
[user@relayfromhost user]$ telnet smtphost 25
Connected to smtphost (IP here).
Escape character is '^]'.
220 smtphost ESMTP Postfix (Ubuntu)
MAIL FROM: root@relayfromhost
250 2.1.0 Ok
RCPT TO: an_email@address.com
250 2.1.5 Ok
DATA
354 End data with <cr><lf>.<cr><lf>
Hello,
This is a test email
.
250 2.0.0 Ok: queued as 58AFD4063F
QUIT
221 2.0.0 Bye
Connection closed by foreign host.
That is all. Testing done through telnet, entering ordinary ascii commands to the SMTP server. Cool!
