in-addr.arpa subdomain problem

[Simon Hobson]

lancer81 at cablespeed.com wrote:

>I am setting up a new server running bind 9.2.1 to replace
>a bind 8.1.2 server. In testing this I am able to do
>reverse lookups on class C subnets but not subdomains
>(e.g. /25). If I am reading dig output properly the server
>is directing request to root servers rather than handling
>it locally.
>
>------------
>
>zone    "128-255.12.12.12.in-addr.arpa" in {
>          type master;
>          file "12.12.12.128.reverse.db";
>          allow-update { none; };
>};
>
>------------
>
>;12.12.12.128.reverse.db
>;
>$TTL 3h
>@ IN SOA ns1.domain.com. hostmaster.domain.com. (
>                  2004080501      ; serial
>                  3h      ; refresh
>                  1h      ; retry
>                  15d     ; expire
>                  1h )    ; neg cache ttl
>
>@       IN      NS      ns1.domain.com.
>@       IN      NS      ns2.domain.com.
>
>129     IN      PTR     host1.domain.com.
>130     IN      PTR     host2.domain.com.
>
>------------
>
>[user at ns1]# dig @ns1 12.12.12.129
>
>; <<>> DiG 9.2.1 <<>> @ns1 12.12.12.129
>;; global options:  printcmd
>;; Got answer:
>;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 29600
>;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1,
>ADDITIONAL: 0
>
>;; QUESTION SECTION:
>;12.12.12.129.                 IN      A
>
>;; AUTHORITY SECTION:
>.                       10800   IN      SOA
>     A.ROOT-SERVERS.NET. NSTLD.VERISIGN-GRS.COM. 2004080401
>1800 900 604800 86400
>
>;; Query time: 16 msec
>;; SERVER: 13.13.13.13#53(ns1)
>;; WHEN: Thu Aug  5 10:51:12 2004
>;; MSG SIZE  rcvd: 106

Apart from the earlier comment that your query is wrong, it is 
actually correct that your name server will go to the root servers. 
What happens is this :

You lookup 128.12.12.12.in-addr.arpa

The nameserver will traverse the heirarchy (starting at the root 
servers) looking for a server that knows about this name.

In all probability, it would end up at a server with a zone for 
12.12.12.in-addr.arpa and here is the fun bit ...

In the zone 12.12.12.in-addr.arpa, there must be a pointer which 
delegates the record to your nameserver :
128	PTR	128.128-255.12.12.12.in-addr.arpa.

This name server will also need the glue records for your name server :
128-255.12.12.12.in-addr.arpa NS xxx.xxx.xxx.xxx

There is actually an RFC for doing just this, but it's number escapes me.

Simon

-- 

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Simon Hobson MA MIEE, Technology Specialist
Colony Gift Corporation Limited
Lindal in Furness, Ulverston, Cumbria, LA12 0LD
Tel 01229 461100, Fax 01229 461101

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