[Mimedefang] more about SMTP+SPF support

[Jeremy Mates]

* Kenneth Porter <shiva at sewingwitch.com>
> SPF also works with those of us who don't have control of our reverse
> zones for outbound direct-to-MX mail; the record goes in the domain's
> forward zone, not it's reverse.
> 
> <http://spf.pobox.com/wizard.html>

Indeed; and for the hosting folks, there is also a modifier that
makes it possible to forward a whole bunch of domains to a single set
of DNS records.

There is also a Mail::SPF::Query CPAN module which makes integrating SPF
support into MIMEDefang trivial:

http://search.cpan.org/perldoc/Mail::SPF::Query

Now to bug my ISP to fix my DNS records...