CIDR example for BIND

[Jeff Stevens]

I'm having a customer that wants to do CIDR reverse lookups but I can't seem 
to find an example for the subnet x.x.x.x/26 case and the range 
x-y.x.x.in-addr.arpa. case.  I assume both notations are allowed in a 
named.conf file?  I'm trying to build a sample named.conf with DB files that 
can illustrate this using both cases.

Customer has a partial Class 3 subnet assigned to him: 12.145.185.192 
through 12.145.185.255.  The reversing DNS entry for his email server 
(12.145.85.236) is coming from AT&T as 236.192/26.185.145.12.in-addr.arpa.

A link with examples would be great...
-- 
Jeffrey Stevens