[PLUG] Virus and SPAM scanning implemented for PLUG mail.

[Karl M. Hegbloom]

I've installed and set up "AMaViS" with the "clamav" virus scanner, as
well as Spamassassin.  These are run by Exim for all incoming email to
lists.pdxlinux.org.  Virus email is quarantined, and the person who sent
it is sent a notice regarding the virus, so they'll know they've been
infected.  Mail flagged as SPAM has the subject line modified, with the
string "*****SPAM*****" prepended.  The Mailman list software
configuration allows a list of expressions that if one matches a mail
header, that mail is held for moderator approval rather than sent out to
the list members.  I've added an expression to match SPAM tagged email.

You may test this by sending SPAM and virus email to the "PLUG-test"
list, or even straight to the normal "PLUG" list if you like.  It SHOULD
not show up at all now, even if you're a subscriber.

After we are all comfortable with this, I suggest that we open the list
back up to allow non-member posting again.

If anyone wants to know how it was done, just log into
drizzle.pdxlinux.org and look over the "/etc/exim/exim.conf" file along
with the conffiles for amavis, clamav, and spamassassin.