Windows CMD: Diagnose DNS and Flush the Client Cache
An internal name still resolves to an old address. Compare cached and authoritative answers, clear the cache, and query again. Work through it yourself in the live host terminal below.
Symptom
An internal name still resolves to an old address. Compare cached and authoritative answers, clear the cache, and query again.
Your mission
Inspect, recover, then verify
Format
Windows Command Prompt
Investigate before you configure.
Use the CLI evidence to isolate the fault, make the smallest safe correction, then verify the network state changed.
Observe the symptom and link state.
Diagnose by comparing the protocol evidence.
Verify the expected device state and confirm the original symptom is resolved.
Console access: Command Prompt
This workspace stacks for portrait phones. Rotate to landscape for the full split-screen console.
Need a hint?
Reveal the root cause when you're ready.
Try the investigation first, then use this as your escape hatch, not a dead end.
Lab debrief
Turn the session into a repeatable troubleshooting pattern.
Use this reference after your attempt: first explain the symptom, then verify the evidence, then confirm the repair.
The problem
`intranet.lab.example` opens the retired server at 10.20.30.80 even though DNS now returns 10.20.30.90.
What you'll practice
- Display cached resolver records
- Query the default DNS server with nslookup
- Query a specific DNS server
- Flush the Windows DNS client cache and retest
The topology
One Windows client uses DNS server 10.20.30.53. The local resolver cache has an old A record while the DNS server has the updated record.
Commands to run yourself
The real diagnostic commands for this lab, copy-paste ready. Run these in the same order to reproduce the investigation on your own session.
ipconfig /displaydnsnslookup intranet.lab.examplenslookup intranet.lab.example 10.20.30.53Topology diagram
Fact-checked references
The commands and behaviour in this lab were checked against these primary references.
Frequently asked
Does flushing the cache change the DNS server?
No. It removes locally cached answers. It does not edit adapter DNS server addresses or records stored on the DNS server.
Why query a specific DNS server?
It lets you compare the configured resolver with a known server and helps identify inconsistent DNS servers.
Ready to run this lab yourself?
No setup, no image sourcing. Book a session or ask for a live demo.