We pick l.root-servers.net, one of the 13 root servers (1), and ask it about mail.qatargas.com.qa and learn that qa is delegated to eleven name servers (2), so we ask a.registry.qa where we learn that qatargas.com.qa is delegated to four name servers, including ns3.qatargas.com.qa (3), so we ask that one where we see a CNAME from mail.qatargas.com.qa to wmail.qatargas.com.qa, so we have to start all over again. We already know that ns3.qatargas.com.qa is authoritative for qatargas.com.qa (4) and ask it about wmail.qatargas.com.qa and learn that wmail.qatargas.com.qa is delegated to three name servers (5), so we ask rlgns1.qatargas.com.qa and get the following answer: