I’ve not experienced this problem sending emails via IPv6 to gmail destinations from my personal domain.
(delong.com <http://delong.com/>) Likely this email will, in fact, get sent to GMAIL via IPv6. I do have good SPF and DKIM records and signing and a reasonable DMARC policy set up. If ISC doesn’t have that yet, it might be a better alternative than turning off IPv6. If that doesn’t solve it, I can reach out to someone at Google who can likely get the right parties involved. Owen > On Apr 2, 2022, at 15:23, Jeroen Massar via NANOG <[email protected]> wrote: > > Hi Dan, > > Hope the rest of the world is treating you decently! > > There are a lot of bits and bobs that one has to get right for mail to flow, > amongst which: > > - IP -> PTR lookup -> that hostname lookup, and match to IP again > (https://en.wikipedia.org/wiki/Forward-confirmed_reverse_DNS) > - SPF > - DKIM > - DMARC > - ARC (for mailinglists) > - SRS (When forwarding, rewrite the From and resign DKIM, and then ARC-sign > that) > - Decent TLS > - MTA-STS > > And that list grows and grows... and grows and grows. It is kinda a test if > one has actually bothered to configure a setup, and not just are randomly > sending an email by just telneting from a random server. Of course the large > spam outfits have this fully automated and configured, so that their > spam^Wadvertising comes through. > > A wee little test tells that there are a few improvements to be made at > minimum: > > https://internet.nl/mail/isc.org/ > > • Not all authenticity marks against email phishing (DMARC, DKIM and > SPF) > • Failed :Mail server connection not or insufficiently secured > (STARTTLS and DANE) > > > Greets, > Jeroen (who also runs his own full net... and had jeroen@isc for a few > years... ;) ) >
