We pick c.root-servers.net, one of the 13 root servers (1), and ask it about yahoo.sh and learn that sh is delegated to seven name servers (2), so we ask a.ns13.net where we learn that yahoo.sh is delegated to three name servers, including ns5.yahoo.com (3), so we ask that one and get the following answer:
Yahoo.sh is a domain controlled by five domain name servers at yahoo.com. All five of them are on different IP networks. Incoming mail for yahoo.sh is handled by one mail server at .. We are missing the IP:s of one server: .. Yahoo.sh has two IP numbers (220.127.116.11, 18.104.22.168). Both are on different IP networks.