ns2.doorway.no has one IP number , which also has a corresponding reverse pointer. ps.no, nsl.no, dwc.no, gdv.no, cdv.no and at least 75 other hosts use this as a nameserver. doorway.no is a domain controlled by two nameservers at doorway.no themselves. They are on different IP networks. Incoming mail for doorway.no is handled by two mailservers also at doorway.no. They are on different IP networks. doorway.no has one IP number. ns2.doorway.no is hosted on a server in Norway.