O'Reilly logo

Postfix: The Definitive Guide by Kyle D. Dent

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Email Topics

Internet email is a complex subject with many aspects. There are important principles that apply when administering an email system regardless of the MTA you are working with. This section presents a few concepts that will help in understanding later explanations in the book, but you are urged to learn as much about Internet email as possible from the many resources available in books and online.

RFCs

RFCs, or Request for Comments documents, define the standards for the Internet. There are several RFCs relating to Internet email, all of which are relevant to you if you are administering an email system on the Internet. The two most commonly referenced RFCs for email are RFC 821 and RFC 822, which deal with how email messages are transferred between systems, and how email messages should appear. These documents were put into effect more than 20 years ago. They were updated in April 2001 with the proposed standards RFC 2821 and RFC 2822, although you will still see many references to the original documents. RFC documents are maintained by the Internet Engineering Task Force, whose site is available at http://www.ietf.org/.

Email Agents

Chapter 1 introduced several of the email agents involved in message composition to final delivery. For convenience, Table 2-1 contains a summary of these agents.

Table 2-1. Email agents

Agent

Name

Purpose

MUA

Mail User Agent

Email client software used to compose, send, and retrieve email messages. Sends messages through an MTA. Retrieves messages ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required