Drop mail to same domain via different relay

Question

OK, this is a slightly convoluted question.

I have a machine here that collects all our mail from an upstream provider with fetchmail, and stores it in our office for collection via IMAP4.

We also have a postfix install that we use for outgoing mail in the office to shift it from the outbox quickly and let the server get around to uploading it when it feels ready.

However, my boss just told me that his wife collects her mail via POP3 directly from the upstream provider, and so his mail is not making it to her (because our postfix install is checking for a local user, not finding one and then bouncing the mail).

I can think of two solutions but I'm not familiar enough with the software to implement either

a) Configure postfix with a list of non-local addresses that it should blindly pass onto it's default relay b) Create a local account for her with a single procmail(?) rule saying to bounce the mail off to her real address, however I'd still need to specify which relay to use or it'd loop until it was blackholed.

Cheers

Answer 1

I'd use a transport map for this. See transport(5) for details.

Answer 2

A more extended answer (the man pages are somwhat vague)

Create $POSTFIX_DIR/transport with contents

<address>   <transport>:<host>

so mine looked like

[email protected] relay:mail.mycompany.com

(Bonus points for the difference between relay and smtp)

And then run:

postmap $POSTFIX_DIR/transport

(Again, I think this is optional because I used the hash: type in the config)

and finally I added

transport_maps = hash:/etc/postfix/transport

to $POSTFIX_DIR/main.cf

restarted and I was away.