TECH LITTLE BRAWTAGLOBAL TECHNOLOGY NEWSROOM & LEARNING
LESSON 1 OF 4 / 8 MINUTES

How a name becomes a destination

Your objectiveDistinguish a successful name lookup from a working website.

Understand the idea.

DNS associates names with records. An address record can tell a client where to connect, but does not prove that an application is healthy. A recursive resolver can reuse a cached answer or obtain a new one through the DNS hierarchy. The time-to-live on a record limits how long it may be cached; it is not a promise that the website will remain available for that period.

MAKE IT CONCRETE

A worked example.

Imagine that a browser successfully resolves example.com but receives a connection refusal. The lookup did its part. Investigating whether the server is listening is more useful than immediately changing DNS providers. Conversely, if a name does not resolve, the browser may never reach the connection stage.

Try the reasoning.

Use the request journey below. Select Name lookup, then Connection. Explain to yourself what evidence would distinguish a failure in each stage. These are simulated states, not requests to a real destination.

A SIMPLIFIED REQUEST JOURNEY

DNS supplies records associated with the name. A successful answer does not establish application health.

Conceptual illustration. Selecting a step does not send a network request.
A hostname resolves correctly, but the web connection is refused. What does the successful DNS answer establish?

Carry it into practice.

In an incident note, record the hostname, returned record, observation time and exact connection error separately. That preserves the distinction between stages.

Read the reference: RFC 1034: Domain names ↗