Postfix (software)

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Postfix

Developer:	Wietse Venema and many others
Latest release:	2.3.4 / November 1, 2006
Preview release:	2.4 Snapshot 20061019 / October 19, 2006
OS:	Cross-platform
Use:	Mail transfer agent
License:	IBM Public License
Website:	http://www.postfix.org/

Postfix is a free software / open source mail transfer agent (MTA), a computer program for the routing and delivery of email. It is intended as a fast, easy-to-administer, and secure alternative to the widely-used Sendmail MTA.

Postfix is the default MTA for a number of Unix (-like) operating systems.

It is released under the IBM Public License 1.0 which is a free software licence, but is incompatible with the GPL.

Formerly known as VMailer and IBM Secure Mailer, it was originally written by Wietse Venema during a stay at the IBM Thomas J. Watson Research Center, and continues to be actively developed today. Postfix was first released in mid 1999.

1 Features
2 Structure
3 Base configuration
4 References
5 See also
6 External links

[edit] Features

Transport Layer Security (TLS)
delegation of SMTP policies to an external process (this allows Greylisting) and advanced content filtering.
different databases for maps: Berkeley DB, CDB, DBM, LDAP, MySQL and PostgreSQL.
mbox-style mailboxes, Maildir-style mailboxes, and virtual domains.
address rewriting (envelope and header), VERP, SMTP-AUTH via SASL, and much more.
Milter [1] support
can be compiled on AIX, BSD, HP-UX, IRIX, Linux, MacOS X, Solaris, Tru64 UNIX and, generally speaking, on every Unix-like OS that ships with a C compiler, standard POSIX development libraries and all the libraries required for handling BSD sockets.

One of the strengths of Postfix is its resilience against buffer overflows. Another one is its handling of large amounts of e-mail. Postfix is built as a cooperating network of different daemons. Each daemon fulfills a single task using minimum privileges. In this way, if a daemon is compromised, the impact remains limited to that daemon and cannot spread throughout the entire system. There is only one process with root privileges (master), and a few (local, virtual, pipe) that actually write to disk or invoke external programs. Most daemons can be easily chrooted.

[edit] Structure

See Postfix Architecture Overview

[edit] Base configuration

The main.cf file stores site specific Postfix configuration parameters while master.cf defines daemon processes. The Postfix Basic Configuration tutorial covers the core settings that each site needs to consider.

Configuration settings for a few common environments are discussed in Postfix Standard Configuration Examples.

Address rewriting and mail routing are covered in Postfix Address Rewriting. The full documentation collection is at Postfix Documentation

[edit] References

Kyle D. Dent (2003). Postfix: The Definitive Guide. O'Reilly Media. ISBN 0-596-00212-2.
Ralf Hildebrandt and Patrick Koetter (2005). The book of Postfix : state-of-the-art message transport. No Starch Press. ISBN 1-59327-001-1.