On Thu, Oct 25, 2018 at 08:11:35AM +0200, Poliman - Serwis wrote:
Hi. I heard that having a non-functional server as the primary MX is a
well-known trick to reduce the amount of incoming spam, as most software
used by spammers will only ever try the highest-priority MX. How to do this?
On 25/10/18 07:33, Viktor Dukhovni wrote:
No. This is a myth, and reduces the reliability and performance
of legitimate email delivery. Use a decent RBL, postscreen(8) may
help to reduce the load on the server and keep smtpd(8) more available
for legitimate email.
On 25.10.18 10:55, Allen Coates wrote:
Yesterday, my Postscreen blocked 92 percent of incoming connection attempts:-
this is not related to the subject of discussion, is it?
There are some anti-spam projects which offer MXes for your use.
You set one up with the LOWEST prioity (your "MX of last resort"); If a message
reaches it, the MX will collect stats
and then return a TEMPFAIL.
but that is the opposite - you provide the lowest MX, not the primary.
Legitimate mail would not be affected as a retry will be forced, though you
may want to find out what the project does with the stats they collect.
I have already encountered case where the mailserver got blacklisted,
because one domain only had two MX-es - primary and the blacklisting one.
Thus, you only should "donate" your MX to such anti-spam projects when you
are 100% sure you have enough of backup MX servers with different uplinks.
yes, such projects should test that, too.
--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
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Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
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