220-1102 Question 103
Single answerNetworkA technician is troubleshooting a Windows 11 laptop that can connect to the corporate Wi-Fi and reach internal resources, but users cannot browse any external websites. Pinging the local default gateway succeeds, and pinging a public IP address such as 8.8.8.8 also succeeds. However, browsing to www.example.com fails on multiple browsers with a message indicating the server name cannot be found. Other devices on the same wireless network can access the internet normally. Which of the following should the technician check FIRST on the affected laptop?
- A
Whether the laptop has an incorrect DNS server configured
- B
Whether the wireless adapter is using the wrong SSID
- C
Whether the laptop's subnet mask is set incorrectly
- D
Whether the default gateway address is missing
Show answer and explanation
Correct answer: A
Explanation
This question tests the ability to distinguish between general network connectivity issues and DNS-specific problems. A classic troubleshooting approach is to compare name-based access with IP-based access. If a client can reach a public IP address but cannot reach an external website by name, the issue is usually DNS resolution rather than Wi-Fi association, IP addressing, or gateway configuration. On Windows, a technician would commonly verify settings with tools such as ipconfig /all, nslookup, and by checking adapter IPv4/IPv6 properties. This aligns with standard troubleshooting methodology and common enterprise support practices: verify connectivity to the gateway, verify internet reachability by IP, then isolate name resolution when hostname access fails.
- A. Correct.
Correct. The scenario shows that local network connectivity and raw internet connectivity are working because the laptop can ping both the default gateway and a public IP address. The failure occurs only when using hostnames, which strongly indicates a name resolution problem. The technician should first verify the DNS settings on the laptop, such as whether the configured DNS server is reachable and correct.
- B. Incorrect.
Incorrect. If the laptop were connected to the wrong SSID, it would more likely have broader connectivity issues, such as inability to reach internal corporate resources or inconsistent authentication and policy behavior. The scenario states the laptop can access internal resources on the corporate Wi-Fi, so the SSID is likely correct.
- C. Incorrect.
Incorrect. An incorrect subnet mask commonly causes problems reaching systems outside the local subnet or creates inconsistent routing behavior. In this case, the laptop can successfully reach both the local gateway and a public IP address, which indicates Layer 3 addressing is functioning well enough for routed traffic. That makes the subnet mask a less likely first check than DNS.
- D. Incorrect.
Incorrect. If the default gateway were missing, the laptop would not normally be able to ping a public IP address on the internet unless the destination happened to be on the same subnet, which is not the case for 8.8.8.8. Since external IP connectivity works, the default gateway is already present and functioning.