8.51.193.in-addr.arpa is a domain controlled by three nameservers. Two of them are on the same IP network. ipb.fr, cnrs.fr, msha.fr, fnet.fr, enscpb.fr and at least 49 other hosts share nameservers with this domain. 51.193.in-addr.arpa is a domain controlled by three nameservers. All of them are on different IP networks.