[ExI] Help! - Fwd: Mail delivery failed: returning message to sender

[Dave Sill]

On Tue, Apr 14, 2020 at 9:11 PM Stuart LaForge via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> Any clue as to why about every other email I try to post to the list
> gets returned to me saying that my "PTR is likely forged". What does
> that even mean?


It's a DNS thing. Normal DNS lookups turn a domain name like sollegro.com
into an IP address. A PTR lookup turns an IP address into a domain name.
Only the authoritative DNS server for a domain can do the name->IP
association, but whoever owns an IP address can do IP->name association to
any domain. So a mail server can do simple authentication by taking the IP
of another server submitting mail, lookup up the domain name associated
with it, then looking up the official IP for that name. If those two IPs
don't match, that's a "likely forgery" (or an honest configuration error).

How do I fix this?


Pass the error on to your ISP.


> Should I switch back to my old Yahoo account?
>

Maybe, if they won't/can't resolve the error.

-Dave
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