The best place to learn about Imail's anti-spam possibilities is in the
Imail manual for your version of Imail. The SMTP security options are very
clearly explained. You might also look up spam and smtp security in the
ipswitch knowledge base.
www.lynndust.com has some great info on using Imail's rule-based filtering
for spam defense. People in this list have used that approach to trap
1000's of spam msgs, some with viruses attached.
>1) Is there anyone or entity whereas we could obtain a list of known "IP
>addresses" who have a history of scanning and finding e-mail server SMTP
>addresses, and then using them for SPAM without permission?
There are a couple of "black-hole" subscription sites that allow you to
suck over their lists of black-listed known spammer sites. But your mail
system or anti-spam defenses have to know how to use this
info. Black-listing is illegal in most commercial activity, so be careful
if get involved in black listing.
>I read that enabling reverse authorization DNS look-up is one way, however
>does this not significantly reduce performance?
Imail doesn't support reverse lookups for smtp authentification, but yes,
reverse lookups are an effective contribution and would slow down, probably
considerably, incoming mail. Before I got the reverse domain for my Imail
server fixed up, it/I was not able to participate in the FreeBSD.org's
MajorDomo lists because they used reverse lookups (and have quite spam-free
lists).
>We run Network Associates NT Sheild on our server, which supposedly does
>scan everything coming into the server. However, I am not so sure how well
>it does with e-mails?
There are mail-specific anti-virus products like Norton AV for Internet
Email, or or from TrendMicro, and I suppose Network Asso. must have a
similar email-server specific virus product. These products usually
intercept smtp traffic, scan it, and forward it to the real smtp
destination. If you want to slow down your incoming mail, this is how to
do it! vbg
Another anti-spam product is Lyris Technolgiies' www.MailShield.com, but at
$5000 .... you gotta really have a big spam pb to justify it.
Len
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