> >However, it would mean source hacks to some part of the mail system, to
> >sendmail in my case.  I'm not afraid to dive into sendmail, but it
> >really does seem like an ugly layering violation.  Dunno what else to
> >do, though.
> 
> Could this be a good application of the inetd functionality that mrg
> recently added?  i.e. inetd checks the IP address (or domain) of the
> machine trying to connect to the SMTP port, and refuses the connection
> if it matches a known spam engine.

You would have to make inetd launch sendmail, then.  In the default
configuration, sendmail is running all the time and receiving the
connections by itself.  Starting sendmail from inetd could cause a great
performance loss on busy mail servers...

  -jm

-- 

                     ---> http://www.jmp.fi/~jmarin/ <---