Grant Taylor via Mailman-Users writes: > I'm questioning why domains that do use ARC headers that don't run > mailing lists should not be white listed.
You're misunderstanding. The ARC community doesn't discourage whitelisting other sites. The work to do whitelisting does. Mailing lists are *known* to *frequently* (almost always) break DKIM signatures in a way amenable to repair by ARC.[1] The other main pain points for DMARC are third-party services that are authorized by the owner of a mailbox to send mail "on behalf of", without participation of the adminstrator of the mailbox's domain. An example is invoicing services. These do not benefit from ARC *at all* because they have a valid DKIM signature from the originating domain, who can be trusted for that service, but don't get such a signature from the mailbox's domain as required for DMARC From validation. The other *possible* use case for ARC would be non-mailing list forwarding. But these almost never break the DKIM signature of the originator. I guess large services like GMail can eventually add a feature where a user can configure GMail to recognize and whitelist specific sites where they have mailboxes set to forward to GMail. But I doubt this will ever be a standard feature of MDAs. It will be complex and fragile to implement, and almost never used. Footnotes: [1] Note that I disagree somewhat with John. I suspect that humongous providers like GMail, Yahoo!, and Microsoft will automatically accept ARC in the presence of a RFC 2369 List-* header, and blacklist on bad behavior, as they do now. That's not perfect from a list admin's point of view---it requires a lot of resources to do that well, so small sites probably won't---but it's not too bad. ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org https://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: https://mail.python.org/mailman/options/mailman-users/archive%40jab.org