These UNIX commands have been taken directly from a Terminal window - these are the commands I use - rather than having been composed after the fact. This is *exactly* what worked for me. I've taken pains to choose forms of the commands which should make sense to you even if you're new to UNIX.

Connecting to the SMTP process

At the UNIX prompt start telnet with the name of the target machine (localhost, if the local computer) and the target port (smtp will specify the actual port in use, or 25 if you feel you must enter a numeric value).

Examples of what you type appears in boldface (you'll need some valid username and recipient values for your system configuration).

% telnet localhost smtp Trying ::1... Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 server.geektimes.com ESMTP Sendmail ... helo username 250 server.geektimes.com Hello localhost [127.0.0.1], pleased to meet you mail from:sender@example.com 250 2.1.0 sender@example.com... Sender ok rcpt to:recipient@GeekTimes.com 250 2.1.5 recipient@GeekTimes.com... Recipient ok (will queue) data 354 Enter mail, end with "." on a line by itself This is a test message from sender@example.com to recipient@GeekTimes.com. The next line contains a period followed by the Return key. . 250 2.0.0 g8S87cpB000444 Message accepted for delivery quit 221 2.0.0 server.geektimes.com closing connection Connection closed by foreign host. %