As you can see, we first check .forward files,
then we check if a user's domain is in local.domains and
if yes, we deliver the mail locally.
Then I check if a file in the data/ directory exists
with the name vacation-$local_part and if yes, we push
that to the transport vacation_pipe.
As last thing we check if our user appears in a virtual-domains/*
file.
The problem is: in case a mail comes in, let's say for a
user test@??? and that user doesn't get found
in the virtual_aliases director, the mail could as well be
sent to the vacation_pipe in case a file
vacation-test exists, that might belong to a completely
different user.
Users that match localuser never get to the vacation router.
