On 11.04.24 15:41, Mr. Peng via Postfix-users wrote:
BTW, is spamassassin still a popular option for antispam today? or should I
use rspamd instead?
It still works, but you may need supplementary software as amavis, sagator,
spamass-milter or mimedefang because SpamAssassin only focuses on
classification, not about delivery.
On Wed, Apr 10, 2024 at 10:23 PM Bill Cole via Postfix-users <
postfix-users@postfix.org> wrote:
On 2024-04-10 at 05:46:36 UTC-0400 (Wed, 10 Apr 2024 17:46:36 +0800)
Mr. Peng via Postfix-users <vir...@gmail.com>
is rumored to have said:
> I have been using spamhaus, spamcop, sorbs as the RBL providers for
> antispam.
> But some of the customers speak to me about the FP issues caused by RBL.
> Do you think the three RBL above are reliable in a practical system?
Those are three of the best, but you have to understand that they are
complicated and may not fit YOUR needs.
Spamhaus offers multiple DNSBLs which each has a vey specific definition,
which they aggregate in the "Zen" list which uses reply value to indicate
which component an address listing belongs to. Not all component lists of
Zen are appropriate for all MTAs. Spamhaus is extremely careful about
making each list reliably represent what they claim it represents. They act
quickly on the rare occasions when they inadvertently list sources of
legitimate email.
SpamCop is based on actual feeds of spam from many sources, and when they
list an IP, you can be certain that it recently sent spam. They do not
exempt major mailbox providers who are also major spam emitters. If you use
the SpamCop list as an absolute test, you will reject some legitimate mail
which shares an outbound MTAQ with spam. Reliably.
SORBS is also informed by multiple sources of spam, and like SpamCop they
do not exempt mixed sources. Like Spamhaus, they have both independent
DNSBLs and an aggregated list that uses distinct return values for each
component list, so you need to take that into account when using it, to fit
the different sorts of listings to different interfaces. Like SpamCop, some
of the SORBS components intermittently list major mixed sources.
You really need to look at your DNSBL choices carefully and with an
understanding of your users and their needs. You may want to consider using
them in a more complex filtering tool like SpamAssassin where it is
possible to weight the impact of different DNSBLs to fit your needs and to
make explicit direct exemptions if you like.
--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
I just got lost in thought. It was unfamiliar territory.
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