Computer Networking · Beginner level

Beginner level · Module 3: Basic Network Troubleshooting · Lesson 2 of 3

Reading IP Configuration and DNS

Use ipconfig and nslookup to find configuration problems.

In this lesson you will

  • Interpret ipconfig output
  • Test DNS with nslookup

Key concepts

ipconfig /all169.254 addressesnslookupflushing DNS

The lesson

ipconfig /all shows each adapter's address, mask, gateway, DNS servers and whether DHCP is used.

An address starting 169.254 (APIPA) means the device could not get an address from DHCP — check the cable, Wi-Fi connection and DHCP server.

nslookup example.com tests name resolution. If it fails, check the DNS servers; ipconfig /flushdns clears old cached answers.

Step by step

  1. Run ipconfig /all.
  2. Identify the active adapter's settings.
  3. Run nslookup for two names.
  4. Diagnose any problem.

Practice activity

Diagnose the DHCP and DNS lab faults.

Expected result: Correct diagnoses supported by command output.

Check your understanding

  1. What does a 169.254 address mean?

    Show answer

    The device did not receive an address from DHCP.

  2. Which command tests name resolution?

    Show answer

    nslookup.

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