On Tue, 13 Nov 2001, Michael J. Tubby B.Sc. (Hons) G8TIC wrote:
> > In order to deliver mail to user@???, exim first tries to connect
> > to foo.bar but is blocked with an error 520 "Connection not authorised
> > from this address." Exim does not then proceed to connect to back.up1
> > or back.up2, but gives up the ghost and returns an failed message
> > report back to the sender.
> >
>
> Yes, because its a permenant error, ie. a 5xx error.
Indeed. At some time in Exim's history a bug which caused it to keep
retrying was fixed. This just proves that every bug will be exploited by
someone as a facility if you don't fix it quickly enough. :-)
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.