On Wed, Mar 29, 2017 at 12:44:27PM +0200, Thomas Huth wrote: > On 29.03.2017 08:46, Markus Armbruster wrote: > > "Michael S. Tsirkin" <m...@redhat.com> writes: > > > >> On Tue, Mar 28, 2017 at 06:35:55PM +0100, Peter Maydell wrote: > >>> Hi; it's been pointed out to me that we have a problem with qemu-devel > >>> unsubscribing people because of DMARC. Specifically: > >>> * microsoft.com publishes a DMARC policy that has p=reject > >>> * some subscribers use mail systems that honour this and send bounces > >>> for non-verifying emails from those domains > >>> * the mailing list software (mailman) modifies emails that pass through > >>> it, among other things adding the "[qemu-devel]" subject tag, in > >>> a way that means that signatures no longer verify > >>> * bounces back to mailman as a result of mailing list postings from > >>> microsoft.com people can then cause people to be unintentionally > >>> unsubscribed > >>> > >>> This is kind of painful. https://wiki.list.org/DEV/DMARC has the > >>> Mailman wiki information on the subject. In an ideal world nobody > >>> would use p=reject because it breaks mailing lists. In the actual > >>> world we have a few choices: > >>> > >>> (1) I could set dmarc_moderation_action=Reject > >>> * this means nobody can subscribe if they've set their dmarc policy > >>> to reject (the "if you don't believe in mailing lists we don't > >>> believe in you" policy). > >>> * there is a certain purity to this option, in that it is pushing > >>> the costs of this unhelpful mail config back on the organisations > >>> which have chosen it; on the other hand I'm reluctant to make > >>> life harder for people who are contributing to the project > >>> and who typically don't have much say over corporate email config. > >>> (2) I could reconfigure mailman to try to not rewrite anything that > >>> we think is likely to be signed (in particular not the body or the > >>> subject) > >>> * this means dropping the [qemu-devel] tag from the subject, which I'm > >>> a bit reluctant to do (it seems likely at least some readers are > >>> filtering on it, and personally I quite like it) > >>> * if anybody DKIM-signs the Sender: header we're stuck anyway > >> > >> For the record I'd strongly prefer this option - I tag all list mail > >> and so "qemu-devel" appears twice: in subject and as a tag. > >> Also, if mail is copied to another list, qemu-devel will > >> still appear as gmail de-duplicates email by msg id. > >> I can remove tags I don't care about but can't remove > >> subject prefixes. > > > > Seconded. Mailing lists messing with the subject to "help" users with > > filtering just complicate it. > > > > Filtering on List-Id isn't any harder, and has the added advantage that > > it actually works. > > The problem is that some mail clients are rather limited and you can > only filter via title there - so I guess some people would complain we > removed the tag from the subject.
Do you mean gmail by any chance? In gmail you can filter using list: which isn't well known. This works even if you get same mail through multiple paths. filtering by subject in gmail is extermely unreliable: if you get a copy directly it discards others and so you get an inconsistent mix of messages with and without the subject prefix. In short I suspect filtering by subject works only half-way and most people just don't notice. > Apart from that, I've also seen mailman messing up white spaces in the > body of e-mails, so this likely would only solve parts of this problem. > > Thomas
