Starting earlier today (Feb-20-2025) AT&T/Prodogy/Yahoo started
rejection my users' emails due to my sending-IP-address (204.9.77.40)
allegedly not having rDNS, except it does! This is happening to emails
sent to the email addresses hosted at the following domain names:
prodigy.net
bellsouth.net
att.net
And this error is ONLY happening when connecting to either
144.160.159.21 or 144.160.159.22
When my users emails route to their other IPs - 144.160.235.143 and
144.160.235.144 - those are not having any problems. And I'm not seeing
any such "no PTR" or "no rDNS" rejection messages with any other email
systems that my users send to - and I have very good telemetry on
rejections of emails sent by my system.
HERE IS THE ERROR THAT IS BEING RETURNED:
550 5.7.1 Connections not accepted from servers without a valid sender
domain.flph830 Fix reverse DNS for 204.9.77.40
And other times, this error is returned:
451 4.1.8 Client IP address 204.9.77.40 does not resolve.flpd569.Fix
reverse DNS.For more information email postmas...@prodigy.net
But every time I do rDNS lookups on 204.9.77.40, from all various
systems, I consistently get this answered with "mail.invaluement.com" -
so I can't get it to fail. (And it has RCrDNS since this hostname
resolves back to this same IP address)
I asked my IP provider is they are having any issues with rDNS queries
getting answers - and they claim that they're not having any issues.
Then I tried to email support addresses at AT&T/Prodogy/Yahoo, but they
are also returning back with this same error.
Anyone else having this issue? And suggestions? Is there anyone on this
discussion list who is with AT&T/Prodogy/Yahoo and who can assist this?
Thanks!
Rob McEwen, invaluement
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