Re: [Asrg] Wierd reverse DNS resolution might affect spam filters

[Tony Finch <dot at dotat.at>]

David Wilson <David.Wilson at isode.com> wrote:
>
>Some years ago a colleague told me that some resolvers, when doing rDNS
>lookup with then perform a forward lookup of the hostname, to check that
>the A records for the name contain the IP address with which you
>started.

I believe this is usually done in the applications rather than in the
resolver itself.

>If not true, perhaps it is something which SMTP servers should do
>themselves, before using the rDNS name for authorization.

What do you mean "perhaps"? Decent MTAs (e.g. Exim) have been doing this
for many years.

Tony.
-- 
f.a.n.finch  <dot at dotat.at>  http://dotat.at/
DOGGER FISHER: SOUTHWEST 4 OR 5. SHOWERS. MAINLY GOOD.

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