Mail coming from IPv6 has higher requirements for delivery than mail from IPv4. The theory is that with IPv4 you may be in a situation where there’s legacy code or infrastructure that can’t be upgraded for operational reasons. For reasons of interoperability that is acceptable.
Anyone sending mail over IPv6 has a new(ish) system and there is zero reason to not meet all modern requirements. There is a reputation cost to sending over IPv6 without properly and fully (both SPF and DKIM) authenticating the email message. There may be other issues here in that the domain reputation is bad AS WELL. But the first step is to sign with DKIM and see if that addresses the issue. Given you can send mail from the same domain over IPv4, it seems it’s not the overall domain reputation, but the domain reputation from an IPv6 IP address. Sign with DKIM. laura > On 2 Jun 2020, at 13:32, Stuart Henderson via mailop <mailop@mailop.org> > wrote: > > On 2020/06/02 10:37, Benoit Panizzon via mailop wrote: >> <<< 550-5.7.1 [2001:4060:dead:beef::1 19] Our system has detected that >> this >> <<< 550-5.7.1 message is likely suspicious due to the very low reputation of >> the >> <<< 550-5.7.1 sending domain. > > "due to the very low reputation of the sending domain", I'm surprised > that made it through legal... > >> DKIM is not a solution. I faced too many problems with mailinglists >> and similar which did alter the header and broke DKIM signatures. > > DKIM isn't (or at least shouldn't be) used as an absolute check unless it's > combined with a restrictive DMARC setting - usually it just feeds in to an > overall score. Failing DKIM doesn't mean that people won't see a mail at > all and when combined with other positive scores usually assigned to > genuine mailing list servers, it will often still get through. > > You are likely to need all the tricks in the book to get mail delivered > over IPv6 into gmail (many people just gave up - most of the common open- > source MTAs have methods to avoid delivering over v6 to certain servers > precisely because of this) - DKIM definitely seems to be something worth > doing. > > > _______________________________________________ > mailop mailing list > mailop@mailop.org > https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop -- Having an Email Crisis? We can help! 800 823-9674 Laura Atkins Word to the Wise la...@wordtothewise.com (650) 437-0741 Email Delivery Blog: https://wordtothewise.com/blog
_______________________________________________ mailop mailing list mailop@mailop.org https://chilli.nosignal.org/cgi-bin/mailman/listinfo/mailop
