How Can I Test My SMTP Server

Are you unsure if you setup Postfix correctly, or you seem to be able to connect, but mail isn’t going through? You can telnet into your SMTP server and run a direct mail test from the console.

If you’re on Windows, open a command prompt. If you’re on Mac or Linux, open up a Terminal window. Once you’re ready, you can follow along.

telnet [server ip] 25

When you’re successfully connected, enter these commands line by line, hitting return after each line.

EHLO
MAIL FROM: test@testemail.com
RCPT TO: [your email here]
DATA
[your message here]
.

When you enter a period on a line by itself, the SMTP server will attempt to send the mail out. Once it’s sent, you can type quit and hit return to exit the SMTP console, and verify the mail actually got to you!