[Dovecot] Deliver, sendmail, virtual users, and catch-all addresses

[Eric Loyd]

I have spent a long time looking into this and can't find the answer
I'm looking for, so I'm asking here.  I'm cutting the example down to
just the bare minimums.  This is NOT my actual configuration, but is
sufficient for asking this question:

  How can I use dovecot's deliver LDA to deliver to virtual users, but
then have unknown virtual users fall back to catch-all addresses
defined by sendmail?

Background:

  * sendmail is the MTA.  I do not wish to change this.
  * procmail is the default MDA.
  * deliver is set up per the dovecot documentation as another MDA.
  * mailertable is configured to send mydomain.com to dovecot:dovecot
  * SQL backend for user/passwords

I have it working the way I want with the exception of catch-alls.  I
thought that it might work by adding @mydomain.com to virtusertable,
but sendmail sees the "user not found" return from deliver as the MDA
and bounces the mail to postmaster.

So what I'm trying to accomplish is this:

  Mail from user at external.com to me at mydomain.com
    Deliver to me
  Mail from user at external.com to sales at mydomain.com (virtual)
    Deliver via deliver to sales at mydomain.com
  Mail from user at external.com to foobar at mydomain.com (invalid)
    Deliver to catchall - spam at otherdomain.com

Can someone point me in the right direction.  RTFM is fine if you'll
tell me what FM to R, because I've run out of ideas...

Thanks!

-- 
Eric Loyd