CWS CWS WLAN Troubleshooting 1 — Questions and Answers
Question 1: What tool is primarily used to identify non-802.11 RF interference sources in a WLAN environment?
- Packet sniffer
- Spectrum analyzer (Correct answer)
- WLAN scanner app
- Protocol analyzer
Correct answer: Spectrum analyzer
A spectrum analyzer detects all RF energy across frequency bands, including non-802.11 sources like microwave ovens and Bluetooth devices.
Question 2: A wireless client shows 'Limited Connectivity' despite successfully associating with the AP. What is the most likely cause?
- Incorrect WPA2 passphrase
- DHCP failure or IP address conflict (Correct answer)
- Weak RF signal below -80 dBm
- Mismatched SSID name
Correct answer: DHCP failure or IP address conflict
'Limited Connectivity' means Layer 2 association succeeded but IP address assignment failed, pointing to a DHCP issue.
Question 3: A high retry rate on a wireless AP most commonly indicates which condition?
- Too many SSIDs configured on the AP
- Excessive VLAN tagging overhead
- Poor RF signal quality or channel interference (Correct answer)
- Firmware version incompatibility
Correct answer: Poor RF signal quality or channel interference
High retry rates indicate frames are not being acknowledged, typically due to poor signal, interference, or excessive channel contention.
Question 4: Which Windows command displays the wireless adapter's current IP address and connection details?
- ipconfig /all (Correct answer)
- netstat -an
- tracert /d
- ping -t 127.0.0.1
Correct answer: ipconfig /all
The ipconfig /all command displays all network adapter configuration details including IP address, subnet mask, default gateway, and DHCP info.
Question 5: A single wireless client cannot connect to the WLAN while all other clients work fine. What should be checked first?
- AP channel settings
- DHCP pool exhaustion
- Client's wireless adapter drivers and settings (Correct answer)
- Core switch uplink capacity
Correct answer: Client's wireless adapter drivers and settings
When only one client is affected, the issue is likely specific to that device's wireless adapter, drivers, or configuration rather than a network-wide problem.
Question 6: What does SNR (Signal-to-Noise Ratio) measure in a wireless network?
- The ratio of broadcast to unicast frames on the medium
- The difference in dB between received signal strength and the noise floor (Correct answer)
- The percentage of frames that require retransmission
- The number of associated clients per AP
Correct answer: The difference in dB between received signal strength and the noise floor
SNR is the difference between the received signal strength and the noise floor in decibels; higher SNR values indicate better signal quality and link reliability.
Question 7: During WLAN troubleshooting, a protocol analyzer captures an unusually high number of deauthentication frames. What could this indicate?
- Normal AP beacon broadcast activity
- A potential DoS attack or rogue AP forcing client disconnections (Correct answer)
- Successful 802.11r fast roaming events
- AP firmware update being applied
Correct answer: A potential DoS attack or rogue AP forcing client disconnections
An excessive number of deauthentication frames can indicate a deauthentication flood denial-of-service attack or a rogue AP forcing clients off the network.
CWS CWS WLAN Troubleshooting 1
What tool is primarily used to identify non-802.11 RF interference sources in a WLAN environment?