[Mimedefang] Filter_Sender Mimedefang/Sendmail PTR Exemption List

[rsavage at nuvox.net]

I am experiencing a situation with a sendmail/mimedefang recipe where I
need to exempt a block of IP addresses in which the sender's reverse DNS
configuration has an IP that returns multiple PTR records.   Sendmail
interoperates this as if the sender has no PTR record and rejects the
mail.  After digging around the google search, I have noticed this might
be accomplished if I use the mimedefang 'filter_sender' functionality.  I
am just having difficulty finding clear and precise documentation as how
to configure a 'filter_sender' rule set.   Would anyone happen to know
where I can find examples/documentation?

Any information, suggestions or ideas/leads is greatly appreciated.

Thanks,

-Rory Savage