RFC2317 reverse dns subdelegation HOWTO

[ATC]

How can I subdelegate reverse DNS for any IPv4 subnet? BIND (or any other DNS software) doesn't seem to understand the syntax suggested by RFC2317.

[ATC]

On the delegating server, define the zone "3.2.1.in-addr.arpa":
$TTL    86400
@  IN      SOA     ISP.server.com. hostmaster.ISP.server.com.  (
                                      2010070900 ; Serial
                                      28800      ; Refresh
                                      14400      ; Retry
                                      3600000    ; Expire
                                      86400 )    ; Minimum

                IN      NS      ns1.ISP.server.com.
                IN      NS      ns2.ISP.server.com.

0/28      IN   NS   ns1.CUSTOMER.server.com.
0/28      IN   NS   ns2.CUSTOMER.server.com.
$GENERATE 0-15 $ CNAME $.0/28.3.2.1.in-addr.arpa.

On the other server, define the zone "0/28.3.2.1.in-addr.arpa":
$TTL    86400
@  IN      SOA     CUSTOMER.server.com. hostmaster.CUSTOMER.server.com.  (
                                      2010070900 ; Serial
                                      28800      ; Refresh
                                      14400      ; Retry
                                      3600000    ; Expire
                                      86400 )    ; Minimum

      IN   NS   ns1.CUSTOMER.server.com.
      IN   NS   ns2.CUSTOMER.server.com.

11      IN   PTR   name11.CUSTOMER.server.com.
12      IN   PTR   name12.CUSTOMER.server.com.
13      IN   PTR   name13.CUSTOMER.server.com.

Understand that the name "0/28" in this example means nothing to BIND or any DNS tool. It is used in this example to help you remember it is a /28 subnet beginning at 0 but make no mistake; the name is not parsed or interpreted as anything else than a name. As long as the ISP and CUSTOMER in this example agree on a unique name within 3.2.1.in-addr.arpa, that name could be "0-28", "0-15", "CUSTOMER" or "Magic".

Note that the 'dig -x' convenience option does not use the recommended algorithm for resolving reverse addresses and therefore cannot be used with subdelegated reverse zones. This is a known problem.  Using dig to manually look up .in-addr.arpa records (without -x) works as expected.

See this discussion for more details:
http://www.webservertalk.com/archive69-2007-1-1776197.html

And here is the original RFC:
http://www.faqs.org/rfcs/rfc2317.html