I don't find this to be a surprise. I believe we discussed this specific type of case early in the tree walk discussion. An early proposal was to walk up the tree to find the PSD and then reverse back down the tree to find the org domain (PSD +1). This approach would have provided an identical result to the PSL design for this case, but we concluded the added complexity and potential other issues made it not the best approach.
Up to now, I don't think anyone has suggested that DMARCbis needs to produce 100% identical results with RFC 7489. We know it won't, but the differences are at the margins and we assessed that they're okay. Scott K On February 24, 2023 12:36:03 AM UTC, Barry Leiba <barryle...@computer.org> wrote: >The issue here, Tim, is that the current way of checking the PSL would send >you to the DMARC record for cuny.edu and p=none, while using the new tree >walk would send you to the DMARC record for bmcc.cuny.edu and p=quarantine. > >In this case, it’s showing that the tree walk is the better mechanism, >because it’s pretty clear that it matches the publisher’s intent. But >Elizabeth is pointing out that it DOES change the result, which means that >the result depends upon which version of the DMARC spec the receiving >domain is using. > >Barry > >On Thu, Feb 23, 2023 at 3:51 PM Tim Wicinski <tjw.i...@gmail.com> wrote: > >> >> Elizabeth, >> >> (speaking as a DNS person). I think this is "OK" - at my last job we set >> up DMARC records which stricter in certain subdomains than >> the parent domain. (Now I need to go find the machine where I left my code >> which did all this validation). >> >> >> (As a DNS person I want to find the folks who put in the TXT record for _ >> dmarc.cuny.edu and ask them to quote their string. But that's >> my OCD). >> >> tim >> >> >> On Thu, Feb 23, 2023 at 5:30 PM Elizabeth Zwicky <zwicky= >> 40otoh....@dmarc.ietf.org> wrote: >> >>> >>> I haven’t done extensive research but here is a live example where >>> treewalk will cause a result change. >>> >>> From: is in the domain Ret.bmcc.cuny.edu which has no DMARC record. >>> >>> _dmarc.bmcc.cuny.edu. 300 IN TXT "v=DMARC1; p=quarantine; >>> fo=1; rua=mailto:dmarc_...@emaildefense.proofpoint.com; ruf=mailto: >>> dmarc_...@emaildefense.proofpoint.com" >>> >>> _dmarc.cuny.edu. 3325 IN TXT "v=DMARC1;" "p=none;" >>> "rua=mailto:dmarc_...@emaildefense.proofpoint.com,mailto: >>> post.mas...@cuny.edu;" "ruf=mailto:dmarc_...@emaildefense.proofpoint.com >>> ,mailto:post.mas...@cuny.edu;"; "fo=1" >>> >>> Elizabeth Zwicky >>> _______________________________________________ >>> dmarc mailing list >>> dmarc@ietf.org >>> https://www.ietf.org/mailman/listinfo/dmarc >>> >> _______________________________________________ >> dmarc mailing list >> dmarc@ietf.org >> https://www.ietf.org/mailman/listinfo/dmarc >> _______________________________________________ dmarc mailing list dmarc@ietf.org https://www.ietf.org/mailman/listinfo/dmarc
