[Dovecot] Dovecot 1.2.12 + Postfix + virtual domains: delivering to system users

[Ran Talbott]

As mentioned in my previous posting, I've set up a mailserver for a domain of 
Winboxen,  authenticated through Active Directory.  After some struggles,  I 
finally got that working.  But I also need to receive emails for a few system 
users on the mailserver (like postmaster,  and a couple of accounts set up 
for maintaining the system).

I thought,  based on the way I read the documentation,  that I could just add 
a "userdb passwd",  ahead of the "userdb ldap",  and deliver would find their 
home directory maildirs.  The virtual users would fail the passwd search,  
fall through to the LDAP check,  and deliver would drop their mail into their 
maildirs in the /var/mailstore tree.  I knew the system users wouldn't be 
able to login to the IMAP server,  but this isn't a concern.

Instead,  the system users' mail got bounced,  after an auth check via 
the "master" socket (from Postfix, I guess: it's a transient process) whose 
details don't get logged.  And the virtual users' lookups (done by deliver) 
returned made-up UIDs and GIDs,  and maildir locations 
(/home/<realm>/<username>) completely different from what the LDAP lookup 
normally returns (/var/mailstore/<username>).

So what am I missing here?  I managed to work around this by adding the system 
users to the Postfix virtual.db,  but it would be nice to not need to do 
that.  It would also be nice to neable the system users to check email by 
logging in to the IMAP serve,  but I'm reluctant to even try that after the 
way delivery went completely wonky.

Thanks,

Ran