[Mailman-Users] SPAM Filtering - was:(no subject)

[Mark Sapiro]

On 05/14/2013 12:43 PM, Christopher Adams wrote:

> On another note, what are thoughts about utilizing SpamAssasin or other
> spam software with Postfix and Mailman. It seems that a lot of the traffic
> that is going through the Mailman server is spam, quite a bit which is
> flagged and blocked by using RBLS in  postfix smptd_recipient_restrictions.
> I am seeing upwards to 8,000 messages blocked every day. Is there a more
> efficient way to manage this without making it a full time job? :>)


I don't think I ever replied to this, but spam filtering is the server's
job. It should be done at the 'front door' and mail determined to be
spam should be rejected by the incoming MTA. This avoids the issue of
accepting the mail and later determining that it is unacceptable and
perhaps returning a DSN or responding in some other way to an innocent
3rd party's spoofed address.

SpamAssassin alone is not a total solution, but there are milters for
incorporating SpamAssassin as well as ClamAV scanning into Postfix.

There are also techniques like greylisting which can help in some
environments.

There are also multidimensional solutions such as MailScanner that
incorporate spam and virus scanning with many other tests, but one issue
with MailScanner is it doesn't evaluate the mail until after it is
accepted by the MTA

-- 
Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan