Confused about reverse zone (RFC 2317?)

We have been asked to manage the reverse zone for 12.31.231. This is the
only "third party" reverse zone that I've had to deal with and I'm
having a heck of a time getting my head around it.

Forgive any silly questions, but I've read RFC 2317 and the appropriate
section of DNS and BIND and still don't quite get it.

Reverse of 12.31.231.132 gets me...

132.231.31.12.in-addr.arpa. 81830 IN CNAME
132.128/25.231.31.12.in-addr.arpa.

I cannot seem to figure out the appropriate way to handle this. Here's
what I have...

zone "231.31.12.in-addr.arpa." IN {
type master;
file "hosts/masters/231.31.12.in-addr.arpa-hosts";
allow-query { any; };
};


And in 231.31.12.in-addr.arpa-hosts....

$TTL 86400
@ 86400 IN SOA shaggy.fusionary.com. hostmaster.fusionary.com. (
2004050501
28800
7200
604800
86400)

@ IN NS shaggy.fusionary.com.

140 IN PTR webmail.hendrickson-intl.com.
132 IN PTR mail.hendrickson-intl.com.

If I need to specify the zone different than "231.31.12.in-addr.arpa.",
how do I do that? I've tried "132.128/25.231.31.12.in-addr.arpa." and
"132.231.31.12.in-addr.arpa." with no luck but now I feel like I'm
guessing and in my case that's *always* a bad idea.

Any suggestions or pointers would be most welcome.


--
Jack Baty
Fusionary Media - http://fusionary.com/
Weblog - http://jackbaty.com