RE: Mail relay question

["Ric Messier" <kilroy () WasHere COM>]

Be grateful it's only 5000 in a month. I typically discard 2000-3000 e-mails
a day. I use postfix with a set of rules to discard incoming connections
that might appear to be spam (can't look up hostname, host is on an rbl,
malformed requests, etc). After postfix is postgrey which is a nice piece of
grey-listing software. Finally, I use amavisd with clamav and spamassassin.
There is a nice little log parsing utility for postfix which will tell you
how many messages it discarded, how many it accepted, the hours it accepted
them, the size of the messages for each recipient, etc, etc. I run it
nightly and generally try to keep an eye out for anomalies. 

Of course, I'm not in a particularly usual situation when it comes to a
personal domain. As you might expect, my e-mail address is pretty popular
for people who want to use a fake. I've also had this address for a long
time so it's gotten around a bit. 

I would strongly recommend reading a good tutorial on how e-mail and SMTP in
general works. There are several around. I'm sure google could turn
something up for you. The various books on sendmail, postfix, even Exchange
should provide an overview of how things work. You could also read the STMP
RFC for the answers from the authoritative source. I used to find that books
like Evi Nemeth's System Admininstration series were helpful for giving an
overview of protocols. 

Hope this helps.

Ric