ns3.uklinux.net has one IP number , which also has a corresponding reverse pointer. hbra.net, qehs.net, 0161.net, dawba.com, 2d.uk.com and at least 100 other hosts use this as a nameserver. uklinux.net is a domain controlled by four nameservers at uklinux.net themselves. Some of them are on the same IP network. Incoming mail for uklinux.net is handled by two mailservers also at uklinux.net. They are on different IP networks. uklinux.net has one IP number. ns3.uklinux.net is hosted on a server in United Kingdom.