postfix half-virtual domains

[ctrl]

I'm trying to configure postfix-dovecot-fetchmail (to maildir) on my home server, and I'm facing some difficulties with postfix virtual mailbox configuration.

What I want is... my virtual domain is mydomain.com. Mail for user1@mydomain.com, where user1@domain.com is in virtual_mailbox_maps, should be delivered locally with virtual transport, according to virtual_mailbox_maps.

Mail for anything_else@mydomain.com, where everything_else is *not* listed in virtual_mailbox_maps (and I'm not fetching it with fetchmail), should be delivered thru my isp smtp relay.

The typical case is... I want to fetch mail for myname@mydomain.com, but I want to be able to write to myfriend@mydomain.com, address that I DON'T manage on my server....

Now.. if I PUT mydomain.com in virtual_mailbox_domains, I can receive (with fetchmail) messages for user1@mydomain.com. Fetchmail sends them to postfix smtp and postfix uses virtual transport to put them in maildir folder. If I write something to user1@mydomain.com, messages are delivered correctly directly to maildir folder.

BUT... I can't write messages to anything_else@mydomain.com because, being not listed in virtual_mailbox_maps, they are rejected.

If I DON'T put mydomain.com in virtual_mailbox_domains, I can send messages to anyone@mydomain.com, but I can't receive for/send to user1@mydomain.com, because postfix relays to my isp smtp (looping forever).

What a mess!

Any suggestion?

[Ziplock]

This sounds like open relay territory to me.

Set up an alias (not sure how to do it in postfix) that points user2@mydomain.com to user2@somewhereelse.com. This means that only user2 can be 'relayed' through your server. Otherwise you are opening your server right up.

[ctrl]

Actually, I only trust my local subnet for relay.