Reverse delegation and Subnets

Michael Kjorling michael at
Fri Oct 26 08:40:54 UTC 2001

Hash: SHA1

Well, it's hard to answer this question since you didn't tell us your
IP span. RFC 2317 (classless delegation is a tricky
beast and the naming convention is not mandated; some people use
start-masklength, others use start-end, start, or start/masklength.
Yet others point it into zones which are not under at

If you have a /28 (16 IPs), and UUnet has delegated to you, I suppose they delegated each IP
individually. However, it's also quite possible that your IP range is - in which case it may be that you should set up a
zone with PTRs [0-15] I don't know. Most
likely no one does, and there is no easy way to check without knowing
the IP address in question.

Michael Kjörling

On Oct 25 2001 23:49 -0000, the_fang wrote:

> Hey,
> I use Djbdns, but hopefully this question is generic enough that
> I'm not too off-topic.
> I have a /28 with UUnet, and they've delegated ""
> to my DNS server. I configured Tinydns for, but
> it then doesn't answer queries on any of my IP addresses. Configuring it
> for works fine, but then (obviously?) my reverse
> mappings don't make it out into the real world.
> My question is, are there any special considerations when configuring name
> servers for reverse delegation of a small subnet?
> Any help or advice appreciated. Thanks.

- -- 
Michael Kjörling  --  Programmer/Network administrator  ^..^
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