Postfix (software)
 |
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2009) |
 |
|
| Developer(s) | Wietse Venema and many others |
|---|---|
| Stable release | 2.9.0 / February 1, 2012 |
| Preview release | 2.10-20120130 / January 30, 2012 |
| Operating system | Cross-platform |
| Type | Mail transfer agent |
| License | IBM Public License |
| Website | http://www.postfix.org/ |
In computing, Postfix is a free and open-source mail transfer agent (MTA) that routes and delivers electronic mail. It is intended as a fast, easier-to-administer, and secure alternative to the widely-used Sendmail MTA.
It is released under the IBM Public License 1.0 which is a free software licence.
Originally written in 1997 by Wietse Venema at the IBM Thomas J. Watson Research Center and first released in December 1998, Postfix continues as of 2012[update] to be actively developed by its creator and other contributors. The software is also known by its former names VMailer and IBM Secure Mailer.
Contents |
[edit] Features
- Transport Layer Security
- Delegation of SMTP policies to an external process (this allows greylisting) and advanced filtering (e.g. using policyd-weight, Postfix can check the E-mail meta-information (sender, recipient, client, helo) against various DNSBLs and for RFC compliance, and reject near-certain spam ahead of receiving the body of the messages, lessening server load)
- Delegation of the delivery to an external process (this allows inspection of the header and body of an email)
- Different databases for maps: Berkeley DB, CDB, DBM, LDAP, Memcached, MySQL, PostgreSQL and SQLite.
- Mbox-style mailboxes, Maildir-style mailboxes, and virtual domains
- Address rewriting (envelope and header), VERP, SMTP-AUTH via SASL
- milter support[1] compatible with Sendmail milters
- Compilable on AIX, BSD, HP-UX, IRIX, GNU/Linux, Mac OS X, Solaris, Tru64 UNIX and, generally speaking, on every Unix-like operating system that ships with a C compiler and which delivers a standard POSIX development environment. It is the default MTA on NetBSD.[2]
Postfix has a particular resilience against buffer overflows [3] and can handle large amounts of e-mail.[4] A Postfix system implements a cooperating network of different daemons.[5] Each daemon fulfills a single task using minimum privileges.[5] In this way, if a daemon is compromised, the impact remains limited to that daemon and cannot spread throughout the entire system. Only one process has root privileges (master), and few processes actually write to locations outside the queue directory (local, virtual) or invoke external programs (local, pipe).[5] Most daemons can be easily chrooted and communicate through named pipes or UNIX-domain sockets.
[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.
The Postfix Standard Configuration Examples document discusses configuration settings for a few common environments.
The Postfix Address Rewriting document covers address rewriting and mail routing. The full documentation collection is at Postfix Documentation
More complex Postfix implementations include integration with (for example) SpamAssassin and support for multiple (virtual) domain names, where data in databases such as MySQL can drive complex configurations.[6]
[edit] See also
[edit] Further reading
- 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.
[edit] References
- ^ "Postfix before-queue Milter support". http://www.postfix.org/MILTER_README.html. Retrieved 2010-03-22.
- ^ "The NetBSD Guide. Chapter 27. Mail and news.". http://netbsd.org/docs/guide/en/chap-mail.html. Retrieved 2010-05-10.
- ^ Hontañón, Ramón J (July 10, 2001). Linux Security. San Francisco: Sybex. pp. 166. ISBN 078212741X. http://books.google.com/books?id=wYBbM8ol2McC&pg=PA166&lpg=PA166&dq=postfix+resilient+against+buffer+overflow&source=bl&ots=PQLUXJcGfA&sig=IeKTayHKaZHj_8j4vF-_wD0x3w4&hl=en&ei=Pq7lTNuQKYaglAfY5IzfCw&sa=X&oi=book_result&ct=result&resnum=8&ved=0CE0Q6AEwBw. Retrieved 2011-09-21.
- ^ http://www.postfix.org/QSHAPE_README.html
- ^ a b c "Postfix Architecture Overview". http://www.postfix.org/OVERVIEW.html. Retrieved 2010-03-22.
- ^ Postfix-Tutorial.com: Postfix, Courier/POP, SASL & Spamassassin - with MySQL admin
[edit] External links
- Official website
- http://www.postfixwiki.org/
- Postfix "how to" with configuration examples and explanation
- http://serverkit.org/modules/postfix-policy A high performance Postfix policy delegation server
- http://www.360is.com/06-postfix.htm Postfix introduction and analysis for secure environments
- #postfix on freenode
