seeking input on rbls and anti-spam measures

[Nathan E Norman <nnorman@incanus.net>]

Hi,

I am looking at revamping my mail setup (caveat; I'm not an ISP so
this is somewhat off topic).  Specifically, I'd like to introduce RBL
lookups into the mix; connections to port 25 should be compared to
various RBLs.  So, which RBLs are people using?  Do you drop/reject
connections or simply flag messages?

Also, I've been toying with the idea of maintaining a database of
"known" SMTP senders that seem to be spam free; that is, IPs not on
the RBL and that have connected to me before.  If I receive a
connection from an IP I haven't talked to before, I'd like to run a
quick relay check on that IP.  I don't know whether it would be better
to temporarily reject mail from that IP (4xx code) or just accept mail
and hope for the best.  The latter seems easier to code ...

Finally, I wonder how to tie this all together.  I currently use qmail
which lends itself well to schemes where another program accepts the
incoming connections and hands them off to qmail once the tests have
been passed.  On the other hand, I'm not totally sold on qmail, I
don't have a huge installation so converting is not a big deal.
There's postfix, but I haven't had time to fully investigate how it
works and how to tie anti-spam measures into it.  There's SAUCE which
requires exim; I'd rather not run exim again :-)

Thanks for reading, and thanks in advance for any thoughts.

-- 
Nathan Norman - Incanus Networking mailto:nnorman@incanus.net
  I retract that silly statement.  Somebody slap me.
          -- Roy Smith