[Mimedefang] MX -> 127.0.0.1

[Kevin A. McGrail]

I agree this is really nice, complete and not messy, but I really just don't 
want to use extra, non-stock modules for this.

Unless there is a performance reason, I think the current code is good 
enough to move forward on.  Now we're just nitpicking some code that really 
isn't that hard to grasp ;-)

I'm moving on to the "what to do with the answer now that we have an answer 
stage".

Regards,
KAM

> use NetAddr::IP;
>
> if ($ip->within(new NetAddr::IP("172.16.0.0/12"))) {
>  #return 1;
> }
>
> complete and not messy