I vaguely recall having similar problems with this at Gmail long before this...circa 2017. They seemingly special cased some senders or platforms (remember Tiny Letter?) but not others, and I recall it being painful.
IMHO the days of sending as a domain where you can't authenticate it directly with aligned DKIM are over. A lot of ESPs nowadays just rewrite the visible from domain unless DKIM is specifically configured appropriately. No other workarounds, no sender header, none of that. I can absolutely see somebody compiling a list of the top 100 or 200 or 500 webmail domains (heck, I track 'em on my website) and disallowing their use in a 5322 From if not from easily recognized infrastructure corresponding to a given webmail platform. Could it false positive, sure. But, it could potentially stop a lot of cruft in a way that people might have thought to be a lesser lift than a full SPF/DKIM/DMARC check, and especially if it was something that was built a while ago when folks were more worried about the overhead of signature checks. (Meaning, I wouldn't bother doing something like this now...but maybe I'm missing something.) Cheers, Al Iverson On Fri, May 16, 2025 at 4:35 PM Mark Fletcher via mailop <mailop@mailop.org> wrote: > > On Fri, May 16, 2025 at 10:59 AM Simplelists - Andy Beverley via mailop > <mailop@mailop.org> wrote: >> >> >> The problem, in short, is that when delivering list emails, Yahoo >> requires the header-from email address to be rewritten for some domains >> but not others (regardless of DMARC policy). >> > Yes, we saw that, starting in early November of last year. > >> >> >> Sure, we could rewrite all emails that are being delivered to Yahoo, but >> that seems overkill for such a small percentage of failures. >> > This was the last straw, so to speak, that caused us to switch to re-writing > the From line if a domain has *any* DMARC record. Previously, we did not > re-write the From line for domains with a p=none DMARC record. But that had > the issue where we'd get probably one or two support inquiries a week from > people doing initial rollouts of DMARC, with p=none, then looking at the > resulting reports, and seeing 'problems' with email from us. > > Cheers, > Mark > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://list.mailop.org/listinfo/mailop -- Al Iverson // 312-725-0130 // Chicago http://www.spamresource.com // Deliverability http://www.aliverson.com // All about me https://xnnd.com/calendar // Book my calendar _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
