reverse lookup via "type forward" - possible? realistic? feasible?

[Ian Diddams]

Just built a brand spanking new dns server using bind 9.2.3.
Its working a treat - master for 127.0.0 and resolves external
addresses via root.hints.

It also - as requested by users - (forward) resolves internal domain
addresses via a type forward statement.

here's the named.conf :

options {
        directory "/var/named";
};
 
zone "0.0.127.in-addr.arpa" {
        type master;
        file "127.0.0";
};
 
zone "." {
        type hint;
        file "root.hints";
};
 
zone "wxyz.co.uk" {
  type forward;
  forwarders {
   a.b.c.d;
   e.f.g.h;
  };
 };


where the two forwarders a.b.c.d and e.f.g.h are internal dns servers.

All well and good.

But...  how do I resolve reverse lookups?  e.g. if fred.wxyz.co.uk has
ip
121.122.123.124, how do I use a similar concept (ie type forward) to
resolve that?

Presumably something along the lines of 

zone "123.122.121" {   [or should that just be "121.122.123" ?]
  type forward;
  forwarders {
   a.b.c.d;
   e.f.g.h;
  };
 };

But IF that's true...  and wxyz.co.uk actually has dozens of subnets,
then presumably I would need a "type forward" section for every
subnet?

And if THAT's true, if a new subnet is introduced naturally the
named.conf would need to be updated to reflect it?


Finally, presumably the whole thing could be covered by a forwarder
statement within the options section (and the type forward section
above removed I guess!)...  what effect would that have on the
external resolution (if any) given that the users for reasons best
known to themselves require THIS dns box to resolve external addresses
and NOT the forwarders.  (hope that last bit made sense!).

cheers!

ian