dns reverse lookup on co-lo address space

[Barry Margolin]

In article <devrlu$31a6$1 at sf1.isc.org>, "noc-ops" <aptgetd at gmail.com> 
wrote:

> Sorry for not being explicit in my explanation.
> 
> I meant to say resolving names to individual ip addresses and
> vice-versa.
> 
> Just so that I'm clear, can the co-lo's reverse DNS add 10.0.16.172
> (off their address space) to their reverse zone file which will
> essentially resolve to hostname.domain.com?

Of course.  What could possibly prevent them from adding

10.0.16.172.in-addr.arpa. IN PTR hostname.domain.com.

to their zone file?

> How can they delegate the reverse DNS, portion of their address space
> to my nameserver (domain.com)? I guess that's what I'm trying to
> understand.

Yes.  If 172.16.0.0/16 is assigned to them, and they assign 
172.16.0.0/24 to you, they simply add:

0.16.172.in-addr.arpa. IN NS ns1.domain.com.
                       IN NS ns2.domain.com.

to their zone file.

If you've been assigned a block smaller than a /24, the technique in RFC 
2317 would be used.

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***