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Re: [Qemu-devel] qemu-devel mailing list vs DMARC and microsoft.com's p=
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] qemu-devel mailing list vs DMARC and microsoft.com's p=reject policy |
Date: |
Tue, 28 Mar 2017 21:28:06 +0300 |
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.
> (3) I could set dmarc_moderation_action to Munge From, which means that
> those senders who have a p=reject policy will get their mails
> rewritten to have a From="Whoever (via the list) <address@hidden>"
> and their actual email in the Reply-to:
> * if anybody's mail client doesn't honour Reply-to: then what they
> think is a personal reply will go to the list by accident
> (4) I could do nothing, and hope that we don't get so many of these
> that they actually result in unsubscriptions
> * in any case emails won't end up going through to some recipients,
> so this isn't much of an option anyway
> (5) I could set the bounce processing config to be (much) less aggressive
> * this seems like a bad idea
> * in any case people whose systems honour DMARC still wouldn't get
> mails from the p=reject senders
>
> I don't really like any of these choices.
>
> For the moment I have picked option (3), but I'm open to argument
> that we should pick something else.
>
> thanks
> -- PMM
Is there a way not to munge the name? It's currently rewritten to
add "via qemu-devel" which confuses the clients which think
it's part of the name, and can't be easily stripped away.
--
MST