0.188.83.in-addr.arpa is a domain controlled by two nameservers at dns.swip.net. They are on different IP networks. op.se, mm.se, jgv.se, ssi.se, flt.se and at least 100 other hosts share nameservers with this domain. 188.83.in-addr.arpa is a domain controlled by four nameservers. All of them are on different IP networks.