30.217.63.in-addr.arpa is a domain controlled by three nameservers at cais.com. Two of them are on the same IP network. cbc.org, sensi.net, eleview.com, ptuning.com, fintrac.com and at least 46 other hosts share nameservers with this domain. 217.63.in-addr.arpa is delegated to two nameservers, however one extra nameserver is listed in the zone. All nameservers are also at cais.com. Two of them are on the same IP network.