On 2/26/21 12:10 PM, b...@uu3.net wrote:
Hmm right... Somehow I tought that having that special Null MX will silently discard message... I dont know why...

It's Friday. I'm presuming that many of us have had a long week and are ready for the weekend. ;-)

So, RFC 7505 is pretty much even pointless in my opinion.

No, it's not pointless. See Alan's reply to my previous message for why a Null MX helps as a sender / MSA operator.

See point #2 in my previous message for why you care about Null MX as a receiver.

You have to do more.. to pretty much achieve the same.

But it's not the same.

You cause hard failures fast. It means that sending servers should never contact the A / AAAA addresses, much less every time the sending system retries to send. So you do save yourself some CPU cycles as a recipient.

Its just easier to not having MX on subdomains that does not serve as email destinations.. Less records in DNS.

Easier has seldom been better.

If you publish a Null MX for said subdomain(s), my server will give up immediately. If you don't publish a Null MX, my server will pester your A / AAAA IPs every four hours for days at a time.



--
Grant. . . .
unix || die

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