Minimizing virus email in queue?

[Tim Tyler]

Mailscanner experts!
  I am running sendmail 8.10 with mailscanner.  I am not sure if this can be
addressed by Mailscanner or Sendmail or neither, but one of the things that
I have observed is that email viruses can add up in the sendmail queue when
it is addressed to a registered domain that for whatever reason is not
accepting a smtp connection.  Therefore, instead of returning to the sender
or postmaster, it sits in queue waiting for delivery for 5 days.
Fortunately, mailscanner removes the body minimizing the size somewhat, but
student infected computers can send out quite a few messages over the course
of 5 days.  Is there a solution that would prevent queueing of virus related
email?  Note: I don't mind messages going to both the sender and recipient
if they can be delivered without sitting in queue.  I just don't like the
message having to wait 5 days.  I also don't want to really change the 5 day
setting as it is appropriate for noninfected email (in my opinion).  So an
ideal solution would be one that tries to process it to the recipient and
sender (if configured) and if it can't be delivered, it discards it instead
of queueing it.  It seems to me that it would have to involve Mailscanner
some how since this should only apply to infected email messages.  Thoughts
anyone?

--
Tim Tyler
Network Manager - Beloit College
tyler at beloit.edu