[Mailman-Users] cause of bounces
Stephen J. Turnbull
turnbull.stephen.fw at u.tsukuba.ac.jp
Thu Oct 19 02:36:31 EDT 2017
Grant Taylor via Mailman-Users writes:
> I use DKIM validity as a signal that I then make decisions based on. -
> Hence why I have chosen to alter spam score on my mail server based on
> the DKIM result.
You can do that. But call it what it is: a deliberate decision NOT to
conform to a standards-track RFC.
The fact of the matter is that the spammers are laughing at you. THEY
have perfectly valid DKIM signatures, or if they're going to try a
replay attack, they remove the DKIM signature they're about to break.
Broken DKIM signatures principally mean somebody added a footer to the
body, a DMARC mitigation in From, or a tag to the Subject. So this
rule primarily targets perfectly legitimate mail posted to mailing
(I don't understand Dimitri's claim about SourceForge ads; all the
mail I get from SourceForge is originated there and AFAIK the DKIM
validates. If it doesn't, their system is pretty brain-damaged.)
Associate Professor Division of Policy and Planning Science
http://turnbull/sk.tsukuba.ac.jp/ Faculty of Systems and Information
Email: turnbull at sk.tsukuba.ac.jp University of Tsukuba
Tel: 029-853-5175 Tennodai 1-1-1, Tsukuba 305-8573 JAPAN
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