ns.jay.net has one IP number , which also has a corresponding reverse pointer. ns1.jay.net cnames to this hostname. se.dk, lpm.dk, gdc.dk, smi.dk, kam.dk and at least 100 other hosts use this as a nameserver. hostmaster.ns.jay.net are subdomains to this hostname. jay.net is a domain controlled by two nameservers at jay.net themselves. They are on different IP networks. Incoming mail for jay.net is handled by two mailservers also at jay.net. They are on different IP networks. jay.net has one IP number. ns.jay.net is hosted on a server in Denmark.