Author Contact: email@example.com
(simple mail transfer protocol) is a protocol that allows you to send emails.Here are the commands a SMTP server uses to send email to a client computer.
Helo domain.com (this veryfies the connection to the server)
Mail From firstname.lastname@example.org (this tells the server who the mail is getting sent by and any email entered there will appear on the Mail From Tag)
RCPT To email@example.com (This is the email address you are sending the email to)
Data (this is the command that allows you to write in what you would like to appear in the Body of the email)
Subject:-your subject here- (this is a optional command if you want a subject to appear on the email)
To Bill the email for mailing put a single Ò.Ó on a new line on a new line.
1. These commands can be used in any GUI or CLI i suggest a good GUI like Protocol buster (htp://www.theblankpages.com) or if you like telnet Heirophant (http://www.undergroundmac.com/ugmpt).
2. SMTP uses port number 25.
Article from MacHacking.net Knowledge Base: http://kb.machacking.net