ns2.f20.com has one IP number , which also has a corresponding reverse pointer. 123.fi, iku.net, pw2.net, f20.com, mrnu.com and at least 100 other hosts use this as a nameserver. f20.com is a domain controlled by two nameservers at f20.com themselves. They are on different IP networks. f20.com has one IP number. ns2.f20.com is hosted on a server in Netherlands.