dydns1.bt.com has one IP number. bt.com, bt.co.uk, btvsu.net, de.bt.com, msm.bt.com and at least 96 other hosts use this as a nameserver. bt.com is a domain controlled by four nameservers at bt.com themselves. All of them are on the same IP network. Incoming mail for bt.com is handled by five mailservers at intersmtp.com. All of them are on the same IP network. bt.com has one IP number. dydns1.bt.com is hosted on a server in United Kingdom.