problems with virtual_alias_maps

[Tomas Macek]

Hi, I'm confused about how works the map tables in Postfix, I'm using the 
2.4.1 version.

I have setup the virtual_mailbox_domains to return the domain names, for 
that we are the final destination and I have also setup the 
virtual_alias_maps for trivial rewrite of some addresses.

My problem:
The virtual_mailbox_domains DOES NOT contain the domain 'mydomain.com' (it 
looks for it in the PostgreSQL database, the proper row with the domain 
name is not returned).
The virtual_alias_maps contains a map, that returns some alias in the 
'mydomain.com'.

The result is, that when someone from the internet sends the mail to 
the alias of @mydomain.com over my server and if the alias is listed in 
the virtual_alias_maps map, the server will receive the mail and tries to 
deliver it to the aliased mailbox.

The problem is clear: we are not the final destination of the 
@mydomain.com and we are delivering for the aliases in the domain.

Is that a normal Postfix's behaviour or I'm doing something wrong? I was 
looking at the docs Virtual domain hosting and Lookup table overview, but 
couldn't find any answer.

Best regards, Tomas