I found it trivial to modify my own mailing list software to simply rewrite the From header so that the sender and visible from are "the list" instead of "the person." That way the list domain's reputation and policy apply, not the poster's. I recognize that John abhors this as a solution, but I do want to remind folks that there are other options to make everything play together nicely, if desired. Time will tell with regard to what ends up getting most often adopted.
Regards, Al Iverson On Fri, Dec 20, 2013 at 2:32 PM, John R Levine <[email protected]> wrote: >> I don't follow your logic John. Why would the DMARC policy of one domain >> affect the health of the mailing list for subscribers from other domains? > > > One user, who we'll call Mason, is a subscriber to the list. Another user, > who we'll call Franck, subscribes from an address with p=reject. > > Franck sends a few messages to the list. The list adds a subject tag or > message footer which breaks the DMARC signature, and it remails the message > with the list's bounce address, so DMARC fails. Mason's mail system checks > DMARC on the incoming list mail, finds that Franck's DMARC says to reject > it, so it rejects it. After a couple of rejections, the list's automatic > bounce handling removes Mason from the list. Oops. > > This isn't hypothetical -- back when ADSP was new, a couple of > overenthusiastic implementations of ADSP bounced people off the IETF's > mailing lists exactly this way. > > The obvious defense is for list software to check Franck's DMARC on incoming > mail and not to accept his mail if it says p=quarantine or p=reject. I've > already adjusted my lists to do that. It turned out to be a one-line config > fix in majordomo2. > > R's, > John > > PS: If anyone is going to suggest that list software needs to be rewritten > not to break DKIM signatures, please don't. We've had that argument many > times already, list software isn't broken, and it ain't going to happen. > _______________________________________________ > dmarc-discuss mailing list > [email protected] > http://www.dmarc.org/mailman/listinfo/dmarc-discuss > > NOTE: Participating in this list means you agree to the DMARC Note Well > terms (http://www.dmarc.org/note_well.html) -- Al Iverson | Chicago, IL | (312) 725-0130 Twitter: @aliverson / www.spamresource.com _______________________________________________ dmarc-discuss mailing list [email protected] http://www.dmarc.org/mailman/listinfo/dmarc-discuss NOTE: Participating in this list means you agree to the DMARC Note Well terms (http://www.dmarc.org/note_well.html)
