Newbie Question: Is anyone actually using the Null MX (RFC 7505)?
Grant Taylor
gtaylor at tnetconsulting.net
Fri Feb 26 22:51:46 UTC 2021
On 2/26/21 12:10 PM, borg at 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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