3.39. How do I protect my mailing lists against viruses?
From the thread on the mailman-users mailing list at < http://mail.python.org/pipermail/mailman-users/2004-July/038200.html>:
From <http://mail.python.org/pipermail/mailman-users/2004-July/038205.html>, one option is to make the entire list moderated, so that only posts which are approved by the moderators are accepted by mailman. However, this creates a heavy load on the moderators.
From <http://mail.python.org/pipermail/mailman-users/2004-July/038206.html>, another option is to set the maximum allowed message size something really low, such as 15KB. Most viruses are unlikely to be this small, so messages which pass this check are unlikely to be infected, and the moderators can always go in and manually approve the larger messages.
You can also choose to strip all types of attachments, save a few specific types which are known to be safe. Look under the "Content Filtering" section for the web administration page for your mailing list. However, this only works for attachments that are in MIME format, and would not catch attachments that are "uuencoded", for example.
One last option is to implement anti-virus scanning software on your mail server, so that these things are caught and dealt with before they ever get the chance of getting to Mailman.
The information at Mailman + postfix + amavisd-new HOWTO (anti-spam) is oriented towards using amavisd and SpamAssassin in an anti-spam configuration, but you can also use amavisd to tie into anti-virus scanning solutions, such as ClamAV. Of course, you can do similar things with other MTAs (e.g., sendmail, exim, etc...) or other scanning solutions.
Converted from the Mailman FAQ Wizard
This is one of many Frequently Asked Questions.