[Exim] sender_verify when DNS comes down....

Hi all,

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.

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?

--
CU,
Patrick.
"Never run on auto-pilot" - The Pragmatic Programmer