[H-GEN] postfix is doing my head in

[Clinton Roy]

Hey folks,

I'm no sysadmin, and I'm having a problem setting up postfix in the way I need.

We've got a setup that is apparently called split delivery, where the
mail for one domain is handled by a couple of servers:

example.com: teachers.server student.server

So for example a school uses its own server for staff mail, but backs
onto a google appliance for student email.

We're solving this by using a tcp transport_map, so if a mail comes in
for user at example.com, we do a recipient address check on the backend
servers in turn, if we get a match, the tcp transport_map returns that
server. So mail to student1 at example.com gets sent to student.server
and mail to teacher1 at example.com gets sent to teachers.server.

So far, so good.

The problem comes when we add the frontend mail server to the list of backends:

example.com: teachers.server student.server localhost

This is for the case where the number of special teacher accounts is
so small that running another mail server for it is pointless.

There has to be special casing of localhost, otherwise it'll get
itself into a recursive loop of recipient checking against itself.
Currently it can send the mail to our lmtp:unix:/socket which handles
local lmtp delivery. That doesn't handle alias mapping unfortunately.

I've tried to spin up another smtpd server from master.cf that turns
overrides the transport_map with -o transport_map= but that seems to
be ignored; even if send mail specifically to that smtpd that doesn't
use the tcp map, it still ends up using it. The -o option seems to
append options, not set them, is there a way of clearing options with
-o, some sort of NULL value?

cheers,

-- 
Clinton Roy
Software Developer
Netboxblue.com
Total Internet Management
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