[26530] in North American Network Operators' Group
Re: mail does bounce (was: Customers down?)
daemon@ATHENA.MIT.EDU (Owen DeLong)
Sun Jan 2 20:37:30 2000
Date: Sun, 2 Jan 2000 17:33:45 -0800
From: owen@dixon.delong.sj.ca.us (Owen DeLong)
Message-Id: <200001030133.RAA24928@irkutsk.delong.sj.ca.us>
To: owen@dixon.delong.sj.ca.us, sean@donelan.com
Cc: nanog@merit.edu
Errors-To: owner-nanog-outgoing@merit.edu
> On Sun, 02 January 2000, Owen DeLong wrote:
> > I'll take a stab at this:
> >
> > Attempting to resolve a.b.c.d.e.f.g.h.i
> >
> > If you get back a return value from DNS that says
> > "Authoritative answer, a.b.c.d.e.f.g.h.i does not exist"
> > Bounce the mail.
> >
> > If you get back a return that says
> > "Resolving a.b.c.d.e.f.g.h.i timed out without a return"
> > Queue the mail.
> >
> > This also works for i, h.i, g.h.i, f.g.h.i, etc.
>
> I'm happy to agree this is a very sensible thing to do. However,
> there is no requirement for any mailer to do it. Some mailers may,
> but other mailers may not. So it is not very wise to assume all
> mailers work the same as yours.
>
> There is a written recommendation that domains should have DNS
> servers on seperate networks. There is no such recommendation
> that mailers retry or queue mail when they can't reach DNS servers.
>
Sean,
I don't even assume that anyone elses mail system works, let
alone that it works this way, or even complies with the RFC's.
There's way too much MicroSoft stuff out there to believe
any of that. I merely purport that the above is BCP.
Owen
