Adress Rewriting für Postfix
Canonical address mapping
Before the cleanup daemon stores inbound mail into the incoming queue, it uses the canonical table to rewrite all addresses in message envelopes and in message headers, local or remote. The mapping is useful to replace login names by Firstname.Lastname style addresses, or to clean up invalid domains in mail addresses produced by legacy mail systems.
Canonical mapping is disabled by default. To enable, edit the canonical_maps parameter in the main.cf file and specify one or more lookup tables, separated by whitespace or commas. For example:
canonical_maps = hash:/etc/postfix/canonical
In addition to the canonical maps which are applied to both sender and recipient addresses, you can specify canonical maps that are applied only to sender addresses or to recipient addresses. For example:
sender_canonical_maps = hash:/etc/postfix/sender_canonical
recipient_canonical_maps = hash:/etc/postfix/recipient_canonical
The sender and recipient canonical maps are applied before the common canonical maps.
Sender-specific rewriting is useful when you want to rewrite ugly sender addresses to pretty ones, and still want to be able to send mail to the those ugly address without creating a mailer loop.