[exim] RFC 1413 default on debian

Hi All,

I'm wondering why exim4 on debian defaults to making RFC 1413
identification calls on all hosts?

It took me a bit to work out why smtp connections were taking 30
seconds to get a response from the server... setting
rfc1413_query_timeout to 0 resolved the problem but I'm not sure about
the "correctness" of that.

Surely there's a reason why Debian configures it to look up all hosts
and sets the time out to 30...

Ian