On 09.07.20 15:06, Matthew Richardson wrote:
On a related issues there were (perhaps long ago) issues if the A record
for a domain had an SMTP server on it, where email could sometimes be
delivered to that A record rather than the MX. I had (again long ago:
10-15 years) actually seen this occur.
If there is MX record for a domain, a MTA MUST only use MX record when
delivering to that domain.
If there is no MX record for a domain, but an A record is available, MTA
uses default MX with preference of 0 pointing to that A records.
This is how it's defined to work, this is not "an issue about that".
Do people think that this problem could still occur these days? What sort
of transient (presumably DNS) failure might cause an SMTP server to deliver
to A rather than MX?
the only DNS failure that could cause this (and I can think of now) is if
DNS server incorrectly returned NODATA for MX record (effectively saying
there's no MX).
--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
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