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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

next googler who emails me will get an bill for my time in fixing this. i've added you to my invoicing system google.

hmm, my IPv6 PTR record already was set correctly. google's bounce links to support.google.com/mail/?p=IPv .. which fails to mention PTR records and tries to get you hooked on some Google Postmaster Tools BS

guess I'm billing google 1 hour for inconclusive investigation?

@joeyh If Google is bouncing your email, check reverse DNS, SPF, DKIM, and DMARC, make sure they are all configured properly.

But the real problem is, when you have everything and Google starts accepting your mail, sometimes, it still flags your mails via IPv6 and moves it to the spam folder randomly.

And there's no incentive for Google to fix it, I guess, and we had to,

> limit mta for domain gmail.com inet4

But many companies use Gmail with their own domains...

@niconiconi - in exim4 I'm using a domain list. What I would need would be a transport/lookup for MX, not A records in exim... afaik this doesn't exist, so I'm stuck with manually conducted domain lists.... // @joeyh

@joeyh Your life will be so much easier when you send mail to Google via IPv4 only...

@joeyh I'm *THIS* close to just refusing all mail from gmail.

But there's enough mail I care about from there that I hesitate.

@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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