Reverse delegation and Subnets
michael at kjorling.com
Fri Oct 26 08:40:54 UTC 2001
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Well, it's hard to answer this question since you didn't tell us your
IP span. RFC 2317 (classless in-addr.arpa) 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 in-addr.arpa at
If you have a /28 (16 IPs), and UUnet has delegated
0.xxx.xxx.xxx.in-addr.arpa to you, I suppose they delegated each IP
individually. However, it's also quite possible that your IP range is
xxx.xxx.xxx.0/28 - in which case it may be that you should set up a
zone with PTRs [0-15].0.xxx.xxx.xxx.in-addr.arpa. I don't know. Most
likely no one does, and there is no easy way to check without knowing
the IP address in question.
On Oct 25 2001 23:49 -0000, the_fang wrote:
> 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 "0.xxx.xxx.xxx.in-addr.arpa"
> to my DNS server. I configured Tinydns for 0.xxx.xxx.xxx.in-addr.arpa, but
> it then doesn't answer queries on any of my IP addresses. Configuring it
> for xxx.xxx.xxx.in-addr.arpa 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 ^..^
PGP: 95f1 074d 336d f8f0 f297 6a5b 2aa3 7bfd 8a70 e33e \/
Internet: michael at kjorling.com -- FidoNet: 2:204/254.4
"There is something to be said about not trying to be glamorous
and popular and cool. Just be real -- and life will be real."
(Joyce Sequichie Hifler, September 13 2001)
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