Rasmus Andersen wrote:
I have a slightly offtopic question that I hope I can get help with
here. I have a home server, running an MTA for my domain. As of the last
month or so, I have experienced a huge increase in spam and spam
bounces. To combat this, I have upped my MTA's pickyness quite a bit but
would like to up it more. Specifically, I would like to reject mail
where sender says HELO jaquet.dk and/or where the Received line looks
like [EMAIL PROTECTED] (my MTA's Received stamps are of the form
[EMAIL PROTECTED]). Spammers like to use these to 'fake' their way
through.
I'm not sure about blocking a specific HELO request, but I added the
following configuration to my main.cf, and combined with postgrey, my
Spam dropped from 150 per day to around 50 per month:
# Set the server to reject any unauthorised e-mails and set what can
# and can't be sent or received by the server
smtpd_delay_reject = yes
smtpd_helo_required = yes
smtpd_helo_restrictions =
permit_mynetworks
reject_non_fqdn_hostname
reject_invalid_hostname
reject_rbl_client xbl-xbl.spamhaus.org
reject_rbl_client bl.spamcop.net
reject_rbl_client relays.ordb.org
permit
smtpd_recipient_restrictions =
permit_sasl_authenticated
reject_non_fqdn_recipient
reject_unauth_destination
permit
smtpd_sender_restrictions =
permit_sasl_authenticated
reject_non_fqdn_sender
reject_unknown_sender_domain
reject_unauth_destination
# can't move from here as needs to know sender
check_policy_service unix:private/postgrey
permit
smtpd_data_restrictions =
reject_multi_recipient_bounce
permit
I've also added the following lines to prevent clients from trying
address after address in the same connection:
# Limit the number of addresses the remove server can
# send mail to, also adjusting the error calculation level
smtpd_recipient_limit = 3
smtpd_recipient_overshoot_limit = 1
That helped my server and account greatly with no (apparent) risk to
genuine mail either.
--
Jonathan Wright [EMAIL PROTECTED]
http://djnauk.co.uk
cat /dev/random (you never know, you may see something you like!)
2.6.17-gentoo-r3-djnauk-b1 AMD Athlon(tm) XP 2100+
up 57 days, 17:24, 1 user, load average: 0.78, 0.63, 0.30
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