gmail rejects some random subset of email from servers that don't have IPv6 reverse dns set..

so if your hosting provider happens to enable ipv6 autoconfig one happy day, everything breaks with no warning

#google #morons

@joeyh - I added a IPv4-only transport/router in exim4 for exactly that reason. Really annoying...

@ij so you also have correct IPV6 reverse DNS and get these bounces?

@joeyh - yes, several DNS online checker didn't find any issues, everything was ok, but still Google refused to accept the mails.

Sometimes I had the impression that Google tries to resolve the maildomain, not the domain of the smarthost. However, this works fine when delivered via IPv4.


@ij @joeyh In a joy of anti-IPv6 adoption, Google applies different standards for IPv6 and IPv4 mail servers, in particular SPF records are "mandatory" on v6. Wouldn't be surprised if there were more strange requirements.

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