[Dovecot] best choice of user database file to work with postfix?

[Thomas Leuxner]

On Thu, Apr 22, 2010 at 11:18:09AM +0200, Rainer Frey wrote:
> What I don't see here at all (and neither in your Wiki Howto) is how Postfix 
> determines the valid recipients for the domains in virtual_mailbox_domains.

Postfix will expand possible aliases first and determine the final
recipient handing over to Dovecot:

virtual_alias_maps = hash:/etc/postfix/virtual

It will query the recipients by connecting to the socket in its
chroot provided by Dovecot:

service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0660
    user = postfix
  }
  user = doveauth
}

Once it has the homedir it will send it off via LMTP or deliver,
whichever you configured via:

virtual_transport = lmtp:unix:private/dovecot-lmtp
or

virtual_transport = dovecot

> 
> The correct parameter would be  virtual_mailbox_maps, but AFAIK there is no 
> lookup table that read the passwd format from an arbitrary file. So a script 
> that generates a hash/whatever postfix lookup file from the passwd-files would 
> still be necessary.

There is no such thing as a correct parameter from my perspective. I did
not say that alias creation was to be unified/automated. Instead I said I did not even think
this is good practice to me. Anyone with at least a bit of sed/awk knowledge
can kludge it from the flat-files anyway.

> 
> Or do you use recipient validation via LMTP? (I didn't notice a 
> reject_unverified_recipient though) This at least won't work with deliver, I'm 
> not even sure about LMTP.

This is not required in the example and optional at least:

http://www.postfix.org/ADDRESS_VERIFICATION_README.html

Consider that verification is done differently in the example based on the
fact whether the mail is received on Port 25 or injected via the
submission port, completely handled in 'master.cf'. So it has a diverse
set of restrictions.

Regards
Thomas