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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: mail does bounce (was: Customers down?)
On Sat, 1 Jan 2000 [email protected] 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. > > > > 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. Hm. I think you're looking at this from a different angle. Yes. If the domain can't be found because there are no records in the root nameserver, a sane mailer should bounce the message, and in fact, Sendmail does, as shown by the following bounce message from my Sendmail server after a message to [email protected], which doesn't exist: ----- Transcript of session follows ----- 501 5.1.2 [email protected] Host unknown (Name server: northshoretechnologies.org: host not found) The 500-series errors are permanent (fatal) failures. What I was referring to was a situation where the domain does exist in the root nameservers but the authoritative nameservers are unavailable. -- North Shore Technologies http://NorthShoreTechnologies.net 888.480.4NET Steve Sobol, President, Chief Website Architect and Janitor [email protected] My opinions DO, in fact, represent the official opinions of North Shore Technologies Corporation, since I own the company. Thanks for asking.
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