Postfix 2.0.0 [LWN.net]

[This article was contributed by LWN reader Tom Owen]

Wietse Venema released Postfix 2.0.0 on December 23. Originally created as the IBM "Secure Mailer" and released under GPL at the beginning of 1998, Postfix is a drop-in sendmail replacement designed from the ground up to be secure. Venema has a long history in the secure software area; his. TCP Wrappers package has been going into Linux distributions unchanged for five years now. So a new major release of one of his packages is worth a look.

The Postfix 2.0.0 release notes list dozens of new features, changes and fixes, mostly consolidations of patch releases accumulated over the last year. The reason for the major version change seems to be to flag some of the changes listed as incompatibilities with 1.1.0. Few of these will cause problems at most sites but virtual domain admins and those receiving mail for users listed in a table (i.e. not in the local /etc/passwd file) will need to read the upgrade notes with special care.

Postfix's strong spam control gets a substantial upgrade with extra control over DNS checks and a rewrite of the relay blacklist (RBL) handling code with new configuration directives. Content filtering based on regular expression matching in headers and body is improved with finer granularity, faster processing, better handling for MIME and other attachments, a more expressive regular expression language and more options to deal with the messages that match.

The many improvements to MIME handling allow better control over the processing of messages with attachments. Meanwhile, only mail mavens and frustrated crackers will care about the subtle semantic changes in fancier address formats and headers. Sysadmins will mostly be pleased with performance improvements and better logging for Postcript and RBL actions. Features like MacOS X support and the better LDAP client have a narrower appeal.

And of course there are occasional items on the way out:

Sendmail-style virtual domains are no longer documented. This part of Postfix was too confusing.

Postfix administrators will be pleased by 2.0.0. They've seen most of it already in the patch releases, and for such a central piece of infrastructure, that's the way it should be. Postfix is still the same straightforward, rather easy to configure mail server, with excellent compatibility as a sendmail replacement and out of the box security.

And that may be the most important lesson from Postfix: not the secure, flexible, multi-process, untrusting design, not the reduction in the mailer monoculture, not even the lucid and closely documented code. Just that security and ease of use are, sometimes, compatible.

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