Simple Mail Transfer Protocol


Simple Mail Transfer Protocol

[¦sim·pəl ′māl ‚tranz·fər ‚prōd·ə‚kȯl] (computer science) An Internet standard for sending e-mail messages. Abbreviated SMTP.

Simple Mail Transfer Protocol

(messaging)(SMTP) A protocol defined in STD 10, RFC821, used to transfer electronic mail between computers,usually over Ethernet. It is a server to server protocol,so other protocols are used to access the messages. The SMTPdialog usually happens in the background under the control ofthe message transfer agent, e.g. sendmail but it ispossible to interact with an SMTP server using telnet toconnect to the normal SMTP port, 25. E.g.

telnet mhs-relay.ac.uk 25

You should normally start by identifying the local host:

HELO wombat.doc.ic.ac.uk

You can then issue commands to verify an address or expand analias:

VRFY fred@doc.ic.ac.ukVRFY postmaster

or expand a mailing list:

EXPN c-help

You can even send a message:

MAIL From:RCPT To:DATAWhat is the point?.QUIT

This is useful if you want to find out exactly what ishappening to your message at a certain point.

See also Post Office Protocol, RFC 822, sendmail.