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. -- Bill Cole b...@scconsult.com or billc...@apache.org (AKA @grumpybozo and many *@billmail.scconsult.com addresses) Not Currently Available For Hire _______________________________________________ Postfix-users mailing list -- postfix-users@postfix.org To unsubscribe send an email to postfix-users-le...@postfix.org
