Non-Octet Boundary Delegation (RFC 4183)

[Peter Rathlev]

On Thu, 2011-09-22 at 15:56 +0400, Станислав wrote:
> I need to have reverse records for 10.133.24.0/21 (from 10.133.24.1 to
> 10.133.31.254) been resolved by our dns server but other networks (all
> of 10.0.0.0/8 except of 10.133.24.0/21) need to be resolved by
> upstream DNS server and I'm not sure how it's possible to configure
> BIND + DHCPD for it.
> 
> In case I use configuration suggested by Andris it doesn't resolve
> names by IP addresses.
> nslookup 10.133.27.68
> Server:		172.27.1.10
> Address:	172.27.1.10#53
> 
> ** server can't find 68.27.133.10.in-addr.arpa.: NXDOMAIN

That's a problem on the name server (BIND?) and not the DHCP server.

Delegating on non-8-bit boundaries is no problem if it's less than 24
bits. To delegate 10.133.24.0/21 you just delegate the following zones:

 24.133.10.in-addr.arpa
 25.133.10.in-addr.arpa
 26.133.10.in-addr.arpa
 27.133.10.in-addr.arpa
 28.133.10.in-addr.arpa
 29.133.10.in-addr.arpa
 30.133.10.in-addr.arpa
 31.133.10.in-addr.arpa

Keep in mind that this is strictly DNS stuff, and not related to DHCP as
such. ISC DHCPd will have no problem finding and updating the correct
zone as long as your delegations are sane.

-- 
Peter