[sdiy] Test Message

Ben Stuyts ben at stuyts.nl
Mon Dec 12 12:10:10 CET 2016

Hi John,

> On 10 Dec 2016, at 23:33, john slee <indigoid at oldcorollas.org> wrote:
> On 11 December 2016 at 08:34, <ijfritz at comcast.net> wrote:
> > Another test post. None of my recent posts seem to have made it.
> This one did.
> I've noticed that Gmail is warning me that some (not all!) messages to
> this list would have been marked as spam if I didn't have a filter to
> catch them.

Yes, some do. I have a test account on Yahoo mail to check this is happening. The only solution is that you mark then as non-spam and train Yahoo’s or Gmail’s spam filters.

In the beginning, synth-diy.org was on some blacklists because of some bad behaviour of one of our IP-address neighbours. Some ISP’s just block a whole net range then, apparently. gmx.de was particularly bad at this, but after contacting them they whitelisted us.

> Unfortunately mailing list software hasn't caught up with DMARC yet.
> I don't know if this is the problem here, but it's certainly possible.
> There's a section about mailing lists in the DMARC FAQ:
> https://dmarc.org/wiki/FAQ
> Gmail performs DMARC checks on the list messages. Whether that
> causes them to be rejected or not depends on how the sender's
> domain (not the synth-diy.org domain) is configured. If the domain
> owner has configured their domain to request rejection of
> unauthenticated messages, they'll be rejected by any email provider
> performing DMARC checks. More info here:
> https://support.google.com/a/answer/2466580?hl=en
> Every SDIY message I've looked at in Gmail is marked as a DMARC
> failure, which is as I'd expect.

DMARC is a bag of hurt for mailing list operators. Mailman, which we use here, has some workarounds for it (which are not turned on right now): It would mean munging the From: address such that the message seems to come from synth-diy.org and not the original DMARC-signed address. Or wrapping the whole message in an outer message (basically make an attachment from it), and again point the From: header to synth-diy.org. Existing DKIM signatures are broken in any case, because Mailman needs to change headers, add a footer, etc.

The only policy I have set up for synth-diy.org currently is SPF, and that seems to work well.

I am certainly open to suggestions, so if there are any DMARC/DKIM/Mailman experts here, send me an email.


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