Solution (?) for Delegation of < /24 sub-domains

[Mark.Andrews at nominum.com]

> I have been searching for this for a few weeks now, read RFC 2317, read
> "DNS and BIND", read the posts, read the FAQ's, scoured the net...
> Seems like many people are having the same trouble with this.  Well,
> after many failed attempts to duplicate what all the documentation says
> we tried something different.  Maybe this method is already posted, but
> if it is I never saw it, so I figured I'd share it because I know how
> maddening it has been to make this work.
> 
> I don't know if this method has problems, if so I would appreciate
> feedback.
> 
> Here is a sample for a class C subnetted into 4 sub-domains, each
> delegated from the ISP to the clients.  No need for CNAME'ing all the
> IP's.  So far we've only tried this with UNIX BIND 8.2.1 and up.
> Wouldn't work with NT DNS or NT BIND 4.9.7, haven't tried with UNIX BIND
> 
> versions lower than 8.2.1
> 
> In the ISP's named.conf:
> 
> zone "0-63.100.168.192.in-addr.arpa" in {
>      type slave;
>      file "/var/named/db.0-63.100.168.192.in-addr.arpa";
>     masters { 192.168.100.1; };
> };
> 
> zone "64-127.100.168.192.in-addr.arpa" in {
>      type slave;
>      file "/var/named/db.64-127.100.168.192.in-addr.arpa";
>     masters { 192.168.100.65; };
> };
> 
> zone "128-191.100.168.192.in-addr.arpa" in {
>      type slave;
>      file "/var/named/db.128-191.100.168.192.in-addr.arpa";
>     masters { 192.168.100.129; };
> };
> 
> zone "192-255.100.168.192.in-addr.arpa" in {
>      type slave;
>      file "/var/named/db.192-255.100.168.192.in-addr.arpa";
>     masters { 192.168.100.193; };
> };
> 
> Then each in-addr.arpa sub-domain has an equivalent zone in their
> named.conf:
> 
> Sub-Domain A:
> zone "0-63.100.168.192.in-addr.arpa" in {
>      type master;
>      file "/var/named/db.0-63.100.168.192.in-addr.arpa";
> };
> 
> Sub-Domain B
> zone "64-127.100.168.192.in-addr.arpa" in {
>      type master;
>      file "/var/named/db.64-127.100.168.192.in-addr.arpa";
> };
> 
> Sub-Domain C
> zone "128-191.100.168.192.in-addr.arpa" in {
>      type master;
>      file "/var/named/db.128-191.100.168.192.in-addr.arpa";
> };
> 
> Sub-Domain D
> zone "192-255.100.168.192.in-addr.arpa" in {
>      type master;
>      file "/var/named/db.192-255.100.168.192.in-addr.arpa";
> };
> 
> The db files for the sub-domains are laid out standard, like for a full
> class C or larger, nothing special in them.
> 
> Again, I am not an expert and there may be reasons why nobody does it
> this way.  I would really like to know any of those reasons.  It's
> possible that I have just totally missed the boat and this is how
> everyone's doing it, but I figured not likely, seeing all the
> frustration in posts on this topic.  That being said, it is working.  We
> 
> have implemented it with our ISP and in turn with several of their
> customers, so far everthing runs smoothly.
> 
> Jason

	Your ISP will have added appropriate CNAMES to
	100.168.192.in-addr.arpa otherwise it would not work.

	The reason this works is that you would have used unqualified
	names in the zone file and the server will have qualified
	them based on the zone declaration.

	e.g.
	@	IN	SOA ...
		IN	NS  ...
		IN	NS  ...
	65	IN	PTR ...
	66	IN	PTR ...

	However if you had used fully qualified names or $ORIGIN directives
	named would have rejected the records a being out of zone.

	Mark
> 
> 
> 
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com