We pick d.root-servers.net, one of the 13 root servers (1), and ask it about itojun.org and learn that org is delegated to six name servers (2), so we ask a0.org.afilias-nst.info where we learn that itojun.org is delegated to two name servers, including orange.kame.net (3), so we ask that one and get the following answer:
Itojun.org is a domain controlled by two domain name servers at kame.net and itojun.org having a total of five IP numbers. Two of them are on the same IP network. Incoming mail for itojun.org is handled by two mail servers at itojun.org themselves having a total of seven IP numbers. Some of them are on the same IP network. Itojun.org has two IP numbers (2001:2f0:0:8800::1:1, 210.155.141.200). Both are on different IP networks.