Delegating Part Of Class C?

[Michael Voight]

This is well documented in the book DNS&BIND, as well as RFC 2317.

Michael

buffalo at icarus.yml.com wrote:
> 
> Greetings,
> 
> We are using BIND version 8.x. Recently, a large ISP delegated part of a
> class C to us:
> 
> xxx.xxx.xxx.80 through xxx.xxx.xxx.94
> 
> However, when I check the ISP's name servers to see how they delegated the
> IPs to us, I notice that while they are pointing all inquiries to our
> nameservers, they seem to be doing so strangely. When I try to do a
> reverse lookup on one of the delegated IPs on their nameservers, I get:
> 
> > 82.xxx.xxx.xxx.in-addr.arpa
> Server:  delegating.isp.nameserver
> Address:  xxx.xxx.xxx.xxx
> 
> Non-authoritative answer:
> 82.xxx.xxx.xxx.in-addr.arpa     canonical name =
> 82.80.xxx.xxx.xxx.in-addr.arpa
> 
> Authoritative answers can be found from:
> 80.xxx.xxx.xxx.in-addr.arpa     nameserver = our.primary.nameserver
> 80.xxx.xxx.xxx..in-addr.arpa     nameserver = our.secondary.nameserver
> our.primary.nameserver      internet address = xxx.xxx.xxx.xxx
> 
> It appears to me that they are pointing to a record on my nameserver:
> 
> db.xxx.xxx.xxx.80
> 
> However, if I try to create db.xxx.xxx.xxx.80 on my nameserver, and then
> do a reverse lookup on say:
> 
> xxx.xxx.xxx.82,
> 
> my nameserver interprets this as doing a lookup on:
> 
> xxx.xxx.xxx.80.82
> 
> which obviously doesn't work. If I try to set up the the db record as:
> 
> db.xxx.xxx.xxx
> 
> on my nameserver, lookups on my nameserver work. However, no matter how I
> set it up, lookups from outside nameserver don't work.
> 
> Should the delegating ISP just have delegated the IPs to us without
> specifying a db file on our nameservers, or should they have done so, but
> named the db differently?
> 
> Many thanks in advance for any and all responses,
> 
> --Duncan