Many organizations will use their in-addr.arpa zone(s) as an alternative form of poor-man’s IPAM.
It looks like you’ve come across some such organizations. Likely those are simply the free (unassigned) addresses within the organization. Likely there are other similar host names in other /24s in the same organization if they have more than a /24 of total address space. OTOH, organizations which do this tend to be relatively small as it doesn’t scale well to multiple administrators managing the same free pool. Owen > On Sep 22, 2021, at 07:12 , Joel Sommers <jsomm...@colgate.edu> wrote: > > Hello all - > > I am a researcher at Colgate University, working with colleagues at the > University of Wisconsin and Boston University on studying aspects of the DNS. > > We're wondering if anyone here would be willing to share some insight into an > apparent IP address management practice we have observed that is evident > through the DNS. In particular, we've seen a number of organizations that > have a fairly large number of IPv4 addresses (typically all within the same > /24 aggregate or similar) all associated with a single FQDN, where the name > is typically something like "reserved.52net.example.tld". Besides the common > "reserved" keyword in the FQDN, we also see names like > "not-in-use.example.tld", again with quite a few addresses all mapped to that > one name. The naming appears to suggest that this is an on-the-cheap IP > address management practice, but we are wondering if there are other > operational reasons that might be behind what we observe. > > Thank you for any insights you have -- please feel free to respond off-list. > > Regards, > Joel Sommers
