04 Try it yourself Interactive
Each press is one exchange. The middle box is what came back, and the word in it is the whole point: REFERRAL means ask them instead, ANSWER means the walk is over, NXDOMAIN means the name definitively does not exist, and CACHE HIT means nobody had to ask anyone. The row of five chips under it shows which level of the hierarchy is being talked to, and the two cache boxes show what the stub and the resolver are holding at that moment. Pick a record type and the shape of the walk changes: MX comes back with a preference and a name, and a cross-zone CNAME answer forces the resolver to start a second walk on the target name. Switch to Warm cache to run the same lookup again thirteen seconds later and see what it costs then. Nothing plays on its own: Next, Back and Reset, or the arrow keys.