nanog mailing list archives
Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)?
From: Grant Taylor via NANOG <nanog () nanog org>
Date: Fri, 26 Feb 2021 12:03:37 -0700
On 2/26/21 11:46 AM, borg () uu3 net wrote:
Well, I bet my legacy system will bounce it for example...
What specifically is the bounce? I thought the purpose of the Null MX was to do two things: 1) Provide as an MX that can't be connected to.2) Serve as a signal to things that know how to interpret it that no mail is to be expected.
I would expect that some server, if not the MSA, /would/ generate a bounce /because/ the email to the domain is undeliverables.
I cant speak about Sendmail, qmail, Exim.. when they started supporting it.
My Sendmail boxes have been dealing with the Null MX just fine. The aforementioned bounce is /expected/ to tell the sender that the destination address is bad.
So, In my opinion changing already working standards in a way that they arent full compat with old systems is imo bad aproach.
IMHO there is little, if any, effective difference between the Null MX and an MX pointing to an unresolvable name or an non-routed IP. They cause a hard / fast failure in an early upstream MTA thus induce a bounce.
Depending on the MSA, the delivery problem may even be presented to the user as they are submitting the message to the MSA.
-- Grant. . . . unix || die
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Current thread:
- Newbie Question: Is anyone actually using the Null MX (RFC 7505)? Pirawat WATANAPONGSE via NANOG (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? Suresh Ramasubramanian (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? borg (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? Suresh Ramasubramanian (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? borg (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? Grant Taylor via NANOG (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? borg (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? John Peach (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? John Levine (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? Grant Taylor via NANOG (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? Alan Hodgson (Feb 26)
- Re: Newbie Question: Is anyone actually using the Null MX (RFC 7505)? Suresh Ramasubramanian (Feb 26)