223.234.87.in-addr.arpa is a domain controlled by two nameservers at qsc.de. They are on the same IP network. dck.de, udk.de, ryf.de, ggw.de, qsc.de and at least 55 other hosts share nameservers with this domain. 234.87.in-addr.arpa is a domain controlled by three nameservers. Two of them are on the same IP network.