According to MXToolbox my server has a problem.

Please review:

The tool shows a 'SMTP Reverse DNS Mismatch' and I don't have an idea why. My PTR Records look like:

158.22.202.116.in-addr.arpa. 86400 IN PTR 158.22.202.116.pleiades.webmaus.net.

I've also got A/AAAA records added for pleiades. Any hints on where the problem could be?

1 Answer

Reverse DNS: closed PTR-A loop

SMTP servers check "closed loop" of PTR and A records.
IP address -> [ PTR record ] -> Name -> [ A record ] -> IP address
Rogue nets can set PTR to any name they like.

There seems to be no A record for 158.22.202.116.pleiades.webmaus.net.

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