[26526] in North American Network Operators' Group
Re: mail does bounce (was: Customers down?)
daemon@ATHENA.MIT.EDU (Sean Donelan)
Sun Jan 2 17:56:07 2000
Date: 2 Jan 2000 14:54:48 -0800
Message-ID: <20000102225448.3922.cpmta@c004.sfo.cp.net>
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To: owen@dixon.delong.sj.ca.us
From: Sean Donelan <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.
