We pick j.root-servers.net, one of the 13 root servers (1), and ask it about gamethu.vnexpress.net and learn that net is delegated to 13 name servers (2), so we ask e.gtld-servers.net where we learn that vnexpress.net is delegated to two name servers, including ns2.gate.vn (3), so we ask that one where we see a CNAME from gamethu.vnexpress.net to gamethu.net, so we have to start all over again. We already know that b.gtld-servers.net is authoritative for net (4) and ask it about gamethu.net and learn that gamethu.net is delegated to two name servers (5), so we ask fdns1.fpt.vn and get the following answer: