On Tue, 23 May 2023, Tim Jackson via Exim-users wrote:
On 23/05/2023 13:21, Sander Smeenk via Exim-users wrote:
I try to send a message to 'i...@email.postcodeloterij.nl', but Exim
unexpectedly changes that to 'i...@postcodeloterij.slgnt.eu', based on
some DNS queries it seems?
| $ exim -f ssme...@freshdot.net -bt i...@email.postcodeloterij.nl
| i...@postcodeloterij.slgnt.eu
I'm definitely not an expert, but is this not expected behaviour based on
RFC5321 section 5.1 [1]?
"The lookup first attempts to locate an MX record associated with the
name. If a CNAME record is found, the resulting name is processed as
if it were the initial name."
And why does it stop there instead of following the next CNAME chain to
postcodeloterij.slgnt.eu.cdn.cloudflare.net?
I don't know the answer to this, but perhaps it's also defined behaviour in
an RFC somewhere? (or out of spec => undefined?)
That bit is easy:
# host -t mx email.postcodeloterij.nl
email.postcodeloterij.nl is an alias for postcodeloterij.slgnt.eu.
postcodeloterij.slgnt.eu is an alias for
postcodeloterij.slgnt.eu.cdn.cloudflare.net.
postcodeloterij.slgnt.eu.cdn.cloudflare.net mail is handled by 10 mx1.slgnt.eu.
So it does follow the chain through and beyond
postcodeloterij.slgnt.eu.cdn.cloudflare.net
--
Andrew C. Aitchison Kendal, UK
and...@aitchison.me.uk
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