On Fri, 2021-02-26 at 12:03 -0700, Grant Taylor via NANOG wrote: > On 2/26/21 11:46 AM, b...@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.
Exactly. Postfix bounces it immediately with an accurate message: Domain ???.com does not accept mail (nullMX) This seems preferable to waiting hours or days for a bounce due to not being able to connect to the A record on port 25 or w/e.
