Postfix Overview - Introduction - SCN Research

Postfix Configuration - Address Manipulation
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Postfix Configuration - Address
Manipulation
Up one level | Basic Configuration | UCE Controls | Rate Controls | Resource Controls | Address Manipulation
Introduction
Although the initial Postfix release has no address rewriting language, it can do quite a bit of address
manipulation via table lookup. While a message flows through the Postfix system, its addresses are mangled in
the order described in this document.
Unless indicated otherwise, all parameters described here are in the main.cf file. If you change parameters of a
running Postfix system, don't forget to issue a postfix reload command.
All mail:
• Rewrite addresses to standard form
• Canonical address mapping
• Address masquerading
• Virtual address mapping
• Relocated users table
• Mail transport switch
Local delivery:
• Alias database
• Per-user .forward files
• Non-existent users
Rewrite addresses to standard form
Before the cleanup daemon runs an address through any lookup table, it first rewrites the address to the standard
user@fully.qualified.domain form, by sending the address to the trivial-rewrite daemon. The purpose of
rewriting to standard form is to reduce the number of entries needed in lookup tables. The Postfix trivial-rewrite
program implements the following hard-coded address manipulations:
Rewrite @hosta,@hostb:user@site to user@site
The source route feature has been deprecated. Postfix has no ability to handle such addresses, other than
to strip off the source route.
http://www.porcupine.org/postfix-mirror/rewrite.html
6/26/01