[Liverpool] Dealing with Spam

[Neil Bothwick]

On Mon, 30 Nov 2009 11:07:14 +0000, Andrew Williams wrote:

> What are you using for your anti-spam? 

Until last year, I was getting well over 1000 spams per day, until I let
my old domain expire. I use filtering in Postfix to drop the most obvious
stuff with this in main.cf

# HELO restrictions
# See http://www.freesoftwaremagazine.com/articles/focus_spam_postfix
smtpd_delay_reject = yes
smtpd_helo_required = yes
smtpd_helo_restrictions =
        permit_mynetworks,
        reject_non_fqdn_hostname,
        reject_invalid_hostname,
        permit

# Sender restrictions
# See http://www.freesoftwaremagazine.com/articles/focus_spam_postfix
smtpd_sender_restrictions =
        permit_sasl_authenticated,
        permit_mynetworks,
        reject_non_fqdn_sender,
        reject_unknown_sender_domain,
        permit

# Recipient restrictions
# See http://www.freesoftwaremagazine.com/articles/focus_spam_postfix
smtpd_recipient_restrictions =
        reject_unauth_pipelining,
        reject_non_fqdn_recipient,
        reject_unknown_recipient_domain,
        permit_mynetworks,
        permit_sasl_authenticated,
        reject_unauth_destination,
        check_policy_service unix:private/postgrey,
        permit

Then I use greylisting and dspam. I found dspam better than SpamAssassin
a few years ago. Whether there's still a difference is anyone's guess,
but my dspam database is too well trained to switch back.

I'm not aware of having lost any mails due to greylisting, but if you
have a backup mail server, it tends to defeat the system as the mails you
reject go there and it tries to redeliver them, getting round the
greylist, so I may drop this and see if there's a noticeable difference.


-- 
Neil Bothwick

"Everything takes longer than expected, even when you take
  into account Hoffstead's Law." - Hoffstead's Law
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