If you want to keep information for virtual lookups in your
directory, it's only a little more complicated. First, you need to
make sure Postfix knows about the virtual domain. An easy way to
do that is to add the domain to the mailacceptinggeneralid attribute
of some entry in the directory. Next, you'll want to make sure all
of your virtual recipient's mailacceptinggeneralid attributes are
fully qualified with their virtual domains. Finally, if you want
to designate a directory entry as the default user for a virtual
domain, just give it an additional mailacceptinggeneralid (or the
equivalent in your directory) of "@virtual.dom". That's right, no
user part. If you don't want a catchall user, omit this step and
mail to unknown users in the domain will simply bounce.
In summary, you might have a catchall user for a virtual domain
that looks like this:
dn: cn=defaultrecipient, dc=fake, dc=dom
owner: uid=root, dc=someserver, dc=isp, dc=dom
1 -> mailacceptinggeneralid: fake.dom
2 -> mailacceptinggeneralid: @fake.dom
3 -> maildrop: [email protected]
1: Postfix knows fake.dom is a valid virtual domain when
it looks for this and gets something (the maildrop) back.
2: This causes any mail for unknown users in fake.dom to
go to this entry ...
3: ... and then to its maildrop.
Normal users might simply have one mailacceptinggeneralid and
maildrop, e.g. "[email protected]" and "[email protected]".