ns21.bt.net has one IP number , which also has a corresponding reverse pointer. indnss21.bt.net point to the same IP. webport.bt.net, host.btclick.com, 5.143.86.in-addr.arpa, 6.149.81.in-addr.arpa, 18.133.86.in-addr.arpa and at least 100 other hosts use this as a nameserver. bt.net is a domain controlled by three nameservers at bt.net themselves. All of them are on the same IP network. Incoming mail for bt.net is handled by four mailservers having a total of three IP numbers. There are four duplicated IP numbers. Some of them are on the same IP network. bt.net has one IP number. ns21.bt.net is hosted on a server in United Kingdom.