[ILUG] Rewriting addresses in Postfix

[Tony Groves]

Tony Groves wrote:
 > I'm up against a problem with Postfix in that I want to rewrite
 > address headers in certain messages but I can't get it to do it the
 > way I want.
 >
 > An example would be a message sent to an address such as
 > "1234567 at fax". I want to have the To header rewritten as
 > "1234567<fax at domain.com>" (so that the fax number is preserved for the
 > fax server to detect) and the message routed to "fax at domain.com". So,
 > in main.cf I add the line:
 >   canonical_maps = /etc/postfix/canonical_maps
 > and in canonical_maps:
 >   /^(\d+)@fax$/ $1<fax at domain.com>
 > and reload Postfix. The result is that the message gets rerouted as
 > intended, and a new X-Original-To header is added showing the original
 > address, _but_ the To header ends up with just "fax at domain.com",
 > losing the fax number.
 >
 > Can any Postfix expert out there tell me how I can get this working,
 > please?

Colm Buckley wrote:
 > I suggest you use fax+number at domain.com - that way you don't have to
 > worry about the address and comment parts of the To: line being
 > separated.  If the domain.com mail receivers accept + as a delimiter
 > (as many do), fax+anything at domain.com will be treated the same as
 > fax at domain.com.

Paolo Marchiori wrote:
 > May I suggest a completely different approach, using
 > fax+1234567 at domain.com so that the fax number remains encoded in the
 > address and doesn't get removed by any step on its way to the fax
 > system?

Thanks for those tips!
Just a small change to the regex and I'm in business:
   /^(\d+)@fax$/ fax+$1 at domain.com
I haven't tested it with the fax server (still RelayFax on Windows) yet, 
but it looks like it should work.

Tony.