[26492] in North American Network Operators' Group
Re: mail does bounce (was: Customers down?)
daemon@ATHENA.MIT.EDU (sthaug@nethelp.no)
Sat Jan 1 16:16:53 2000
To: sjsobol@NorthShoreTechnologies.net
Cc: nanog@merit.edu, swmike@swm.pp.se
From: sthaug@nethelp.no
In-Reply-To: Your message of "Sat, 01 Jan 2000 15:07:43 -0500"
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Date: Sat, 01 Jan 2000 22:14:46 +0100
Message-ID: <39476.946761286@verdi.nethelp.no>
Errors-To: owner-nanog-outgoing@merit.edu
> > I know for certain that Postfix and Smail will immediately bounce a
> > message when the domain is authoritatively non-existant. I'd be very
> > surprised and dismayed if sendmail and all other true SMTP mailers did
> > not do exactly the same thing.
>
> Sendmail most definitely does not, instead treating the error as a
> transient error, issuing an SMTP error code in the 400 series, and
> continuing to try to send the mail for up to five days (the default),
> or whatever the mail server admin configured for that particular
> server.
>
> I think I like it better that way. Just because both nameservers are
> temporarily down doesn't mean the domain doesn't exist. :P
Seems to me you're talking past one another. If all nameservers for a
domain are down there *is* no nameserver which can say that the domain
is authoritatively non-existent. (OK, you could get a negative caching
answer from one of the authoritative servers on the level above, but
that's a different issue...)
I agree with Greg Woods - if a domain is authoritatively non-existent,
I'd expect a sane mailer to bounce the message.
Steinar Haug, Nethelp consulting, sthaug@nethelp.no
