[exim] dnslists ACL condition

Question for the list:

Should the behaviour of the "dnslist" condition
be changed to default to "=127.0.0.0&127.0.0.0" ?

The existing behaviour is to return true if
any value is retrieved.

The rationale would be that most operational DNSBLs
return values in the 127.0.0.0/8 range, but that
dead ones a) tend to apparently list the world
b) get replaced by parked domain websites, so
return some value outside that range.

The upside would be that you don't suddenly start
rejecting all your mail. The downside is that you'd
never notice, and fix it.
--
Cheers,
Jeremy