Hi Faisal, Do you have a source for this acknowledgement? Because in fact Microsoft is the MTA where we observed the negative influence of ED52119 DKIM signatures, even if accompanied by a valid RSA sig.
Kind regards, Florian -----Ursprüngliche Nachricht----- Von: mailop <[email protected]> Im Auftrag von Faisal Misle via mailop Gesendet: Montag, 17. März 2025 15:53 An: Dan Malm <[email protected]> Cc: [email protected] Betreff: Re: [mailop] IPv6 + DKIM issues with deliveries to Microsoft? Microsoft has acknowledged a bug where if a message has multiple DKIM signatures, and one fails, they fail the entire message - even if the key that passes is aligned and compliant. They blame it on a DNS timeout on their resolvers that they're implementing a fix for starting last week and will gradually be applied to all tenants. I am skeptical, but we shall see. Best, Faisal > On Mar 17, 2025, at 2:46 PM, Dan Malm via mailop <[email protected]> wrote: > > Hi mailoppers, > > I'm currently (and have been for 30+ days) seeing issues delivering messages > to Microsoft over IPv6. > ~10% of messages delivered over IPv6 to Microsoft gets an error like this on > the initial delivery attempt: > > "Service does not accept messages sent over IPv6 [2a02:2350:5:504::1] unless > they pass either SPF or DKIM validation (bad or invalid public-key record). > AS(206)" > > The sending domains getting this all lack SPF, but the messages are always > DKIM signed. And all these messages are delivered successfully after one or a > few retries. ~90% of the successful retries are over IPv6. I.e. the DKIM > signatures with supposedly "bad or invalid public-key record" are accepted on > retry, which to me smells like some DNS resolving issue on MS end... (or some > strange intermittent issue with messages dual-signed with both RSA and > ED25519) > > Anyone else seeing something similar or are we somehow unique in this? And > are there anyone from Microsoft listening that could explain what's going on? > > -- > BR/Mvh. Dan Malm, Systems Engineer, one.com > > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
