The scenario
PC (10.0.1.10) reaches Web-Server (10.0.2.10) through the Router, and DNS-Server (10.0.1.53) sits on PC's own switch with a record for web.corp. Yet every name PC tries fails. The cause is one setting: PC's DNS server is 10.0.1.35, the right digits in the wrong order. No device has that address, so PC's questions go nowhere and nothing answers. The network, the DNS server and the record are all fine.
What you will work out
Learn to tell a name-resolution problem from a network problem, and to check which DNS server a device is really asking.
Why this matters
'The internet is down' often turns out to be 'names are not resolving'. Testing a connection by address, then asking the configured server and a known-good server with dig, separates a broken network from a broken lookup in a minute, and tells you which part of the lookup to fix.
Running it
Names Don't Resolve opens on a canvas, already wired and addressed. Trace a packet through it hop by hop, or run the same topology live on real Linux network namespaces. How the two modes differ.
Open Names Don't Resolve
Runs in your browser. No install, no signup, and the simulation starts instantly.
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