> > Ok, but what happens if  there isn't any  ORIGIN statement ?
> 
> Then you need to specify the entire FQDN

If there is no $ORIGIN, then the origin is (implicitly) the zone that
is specified in named.conf/named.boot.

> > And ,Let imagine that we have a full Class C Address-pool.
> > We assign this Pool to 2 different ISP (0-63) (64 - 127) the remains are
> > assigned to us (128 - 255).
> > Each ISP has his own NameServer.
> 
> Well, this one is more difficult.  Basically, someone who has been
> delegated the entire Class C address space (ie, yyy.xxx.194.in-addr.arpa.)
> has to delegate the pieces.  For example, ISP1 would delegate one piece
> to ISP2.  Then ISP1 would provide PTR records for its own portion of the
> address space, and CNAMES for ISP2's portion:
> 
> 	# ISP 1 addresses
> 	1	IN PTR a1.ISP1.com.
> 	...
> 	62	IN PTR a62.ISP1.com.
> 
> 	# ISP 2 addresses
> 
> 	64	IN SOA ... (to delegate 64.yyy.xxx.in-addr.arpa.)
> 
> 	65	IN CNAME 65.64.yyy.xxx.in-addr.arpa.
> 	...
> 	126	IN CNAME 126.64.yyy.xxx.in-addr.arpa.
> 
> And then, ISP 2 defines the PTRs that the CNAMEs point to:
> 
> 	ORIGIN 64.yyy.xxx.in-addr.arpa.
> 	65	IN PTR 65.ISP2.com.
> 	...
> 	126	IN PTR 126.ISP2.com.
> 
> There's an RFC on how to do this, but I don't have the number off the
> top of my head.

RFC 2317, "Classless IN-ADDR.ARPA delegation". 

Also, not that this is *very* easy to do with BIND 8.2, which has the
$GENERATE statement. This allows ISP1 to generate all the necessary
CNAME RRs. No muss, no fuss.

Steinar Haug, Nethelp consulting, sthaug@nethelp.no