GNU/Linux Desktop Survival Guide
by Graham Williams
You can talk directly to an SMTP server, for example to test that it actually works for you. Here's a sample interaction. The commands don't need to be uppercase -- they are here just to make the commands obvious.
$ telnet mailhost.act.togaware.com 25 Trying 18.104.22.168... Connected to mailhost.act.togaware.com. Escape character is '^]'. 220 mailhost.act.togaware.com ESMTP Postfix helo modern.act.togaware.com 250 mailhost.act.togaware.com mail from: firstname.lastname@example.org 250 Ok RCPT TO: email@example.com 250 Ok DATA 354 End data with <CR><LF>.<CR><LF> Subject: Testing manually through telnet to mailhost This is the body . 250 Ok: queued as 42DDE139919 QUIT 221 Bye Connection closed by foreign host.
The EHLO localhost command will list the capabilities of the server.