View source for Category:Mail Transfer Agents

The concept of a Mail Transfer Agent was first canonicalized in RTF 1506. Its pithy definition is not at all bad:

''An MTA forwards received messages to a next MTA or to the recipient UA (User Agent).''

Mail will be produced on your machine by local processes such as cron or the venerable <tt>/usr/bin/mail</tt>; your MTA delivers it locally, or forwards it closer to its eventual destination. More complex [[:Category: Mail User Agents|user agents]] might bypass the local MTA by performing the MTA function themselves. Mail received on network interfaces is likewise processed by the MTA for local delivery or forwarding. Some MTAs do not support local delivery; some do not support ESMTP to MX records.

A SprezzOS machine must always be running some MTA, so as to implement the <tt>/usr/sbin/sendmail</tt> facility. The default SprezzOS MTA is [[Postfix]].