Chris Turan wrote:
Hey All,
I'm having an issue with backscatter emails and implementing a
before-queue spam and virus scanner. My current mail server uses a
after-queue amavisd-new scanner with spamassassin and clamav. In the
last two weeks, my system has started *sending* a significant number of
backscatter messages.
I need to silence these messages in a safe and reliable way. Here are
my criteria:
1) Reject the message before the end of the smtp transaction.
2) Scan for both spam and viruses.
3) Never discard. MTA must deliver-and-tag or reject-and-notify.
4) Scan both incoming and outgoing messages.
5) Scanner is fast, runs as a daemon, and is preferably written in a
faster language like C.
Despite my best research, I have not yet found a way to do all five of
these. Can anyone recommend a way to run amavis as before-queue
scanner, or to recommend a different scanner better than amavisd-new.
I'm hoping to get some recommendations from the folks here.
-Chris
You need to configure postfix to reject unknown recipients
during SMTP. Switching to something other than amavisd-new
and/or switching to a before-queue filter won't help that.
amavisd-new meets all your criteria, providing you configure
it to tag+deliver mail rather than bounce.
You can configure amavisd-new as a before-queue postfix
smtpd_proxy_filter. Note this mode is not "officially"
supported by the amavisd-new author, but it should work well
for small volume sites. The "small volume sites" is a
before-queue limitation, not an amavisd-new limitation.
If you describe your problem in more detail, you will likely
get more specific recommendations in solving it.
--
Noel Jones
