ns3.b-one.nu has one IP number , which also has a corresponding reverse pointer. ns3.b-one.net point to the same IP. whi.se, bhl.se, tmk.se, nke.no, rld.be and at least 100 other hosts use this as a nameserver. beepsend.se use this as a mailserver. b-one.nu is a domain controlled by two nameservers at b-one-dns.net. They are on the same IP network. Incoming mail for b-one.nu is handled by two mailservers at one.com. They are on the same IP network. b-one.nu has one IP number. ns3.b-one.nu is hosted on a server in Denmark even though the hostname implies Niue.