Lab: DNS and HTTP across a routed network

One client, one DNS server, one web server, a router between them. Small enough that you can break one thing at a time and see exactly what each failure looks like from the client's side — which is where every real ticket starts.

Do this

• Confirm the client can reach the web server by address.
• Point the client at the DNS server and fetch the page by name.
• Then break three things, one at a time, and write down the symptom for

The point

All three present as "the website does not load". They are told apart by the order you check in:

• Ping the address. Works? Then it is a name problem. Fails? Then stop
• Resolve the name against the configured server, then a known one. First
• Both resolve and it still will not load: DNS was never involved.

Ninety seconds, and you have eliminated two of the three before anybody has had a theory.

Try breaking it

• Give the client the right DNS server and a wrong default gateway.
• Leave the record in place but stop the service on the server.
• Add a deny to the router that drops port 80 and nothing else, and see how