Re: [EXIM] Duplicate IDs

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Author: Philip Hazel
Date:  
To: djc
CC: exim-users
Subject: Re: [EXIM] Duplicate IDs
On Wed, 20 May 1998, Dave C. wrote:

> Why does exim consider a 4XX response to MAIL FROM: an "SMTP error"?


It is an error. A temporary error, but nevertheless an error.

> Why doesnt it recognize that it should defer?


It does. Or at least it should. You haven't quoted the final log entry,
which I would expect to be a defer-type entry.

> I'll also note that I've see 5XX codes logged as "SMTP error"s as well,


Indeed. They are permanent errors.

> Exim should consider a 5XX code from a remote SMTP host to mean bounce
> the message or recipient..


It does. Sorry, I guess this is a language interpretation problem. I've
used the phrase "SMTP error" as a shorthand for "error code encountered
as a response to a command during an SMTP session". I know the RFC talks
about reply codes rather then error codes, but then one would have to
use the phrase "non-OK reply code" or something, which is pretty
cumbersome.

I wanted to get the term "SMTP" included, just in case one day Exim gets
fitted with some other remote transport. I wanted to ensure it said
"from remote mailer" because otherwise when these things appear in
bounce messages people assume the problem was detected on the local
mailer, leading to questions like "How can the local mailer possibly
know that xxx@??? is an unknown user?" (I still get queries
like that, despite the presence of the phrase "from remote mailer". Some
people just can't read.)

> SMTP>> HELO smtp.mydomain.net
> SMTP<< 250 XXXXX.com Hello smtp.CNS.net (oak.CNS.net from address
> [205.132.48.7]).
> SMTP>> MAIL FROM: <XXXXX@???>
> SMTP<< 450 defer '<XXXXX@???>',
> sender address target 'XXXX.XXX' cannot be verified at this
> time: verify_sender(): BIND server failure: Nameserver: Server failure:
> Connection timed out. (Try again later)
> LOG: 0 MAIN
> SMTP error from remote mailer after MAIL FROM: <XXXXX@???>: host
> XXX.XXX.com [x.x.x.x]: 450 defer '<XXXXX@???>', sender
> address target 'XXXX.XXX' cannot be verified at this time:
> verify_sender(): BIND server failure: Nameserver: Server failure:
> Connection timed out. (Try again later)
> SMTP>> QUIT
> SMTP<< 221 XXXXX.com closing connection
> LOG: 0 MAIN


-- 
Philip Hazel                   University Computing Service,
ph10@???             New Museums Site, Cambridge CB2 3QG,
P.Hazel@???          England.  Phone: +44 1223 334714



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