ns1.tgv.net has one IP number , which also has a corresponding reverse pointer. ns1.x1.fr point to the same IP. x1.fr, m1.fr, phl.fr, tgv.net, gx1.net and at least 100 other hosts use this as a nameserver. tgv.net is a domain controlled by two nameservers at tgv.net themselves. They are on different IP networks. Incoming mail for tgv.net is handled by one mailserver also at tgv.net. tgv.net has one IP number , but the reverse is ns0.tgv.net. ns1.tgv.net is hosted on a server in France.