On Wed, 21 Nov 2001, Patrick von der Hagen wrote:
> today the DNS came down for one hour and during that period some mail was
> rejected:
> 2001-11-21 09:23:57 verify failed for SMTP recipient user@domain from
> <someone@elsewhere> H=didi.dada [x.x.x.x]
>
> This happened to lots of mails and probalby all of them bounced.
> I definitly have some reports about bounced mails. :-( Looks like exim gave
> a 5xx-error.
I take it that by "DNS came down" you actually mean "my host was unable
do do DNS queries"? Because the DNS as seen from here has been working
fine all day.
> Receiver verifycation is done using OpenLDAP and OpenLDAP checks DNS to see
> which servers are allowed to access the mail-data.
>
> I don't know what went wrong: couldn't exim connect to the LDAP-Server due
> to the DNS-Problem? Or was the connnection refused by OpenLDAP due to DNS?
>
> Most important: the receiver couldn't be checked, probably because the
> connection couldn't be established. Shouldn't exim give a 4xx error instead
> of 5xx?
If Exim's receiver verification code detects a temporary error, if does
indeed give a 4xx error to the RCPT TO command. But without knowing
details of your configuration, I can't say exactly what happened. It
sounds as if the matter is complicated by the presence of LDAP.
Exim should only give a 5xx error if it positively knows the
verification has failed. Timeouts, inaccessibility of databases, etc.,
should give temporary errors.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
