North American Network Operators Group

Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: mail does bounce (was: Customers down?)

  • From: Christian Kuhtz
  • Date: Sat Jan 01 18:30:57 2000

On Sat, Jan 01, 2000 at 03:07:43PM -0500, Steve Sobol wrote:
> > 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.

I beg to differ.
> 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

Or, worse, there's a glitch in the root servers or the registry maintaining
the authoritative data.  Or everything's fine on that side and the mail server
receiving the message has been temporarily disconnect from the 'global truth'.
Better to queue temporarily and treat it as a transient failure than to drop.  

That's almost always the best approach for loosely coupled systems, IMHO.


Christian Kuhtz                                     Architecture,
<[email protected]> -wk, <[email protected]> -hm                       Atlanta, GA
                                                    "Speaking for myself only."