Practice Free CWNA-109 Exam Online Questions
The ACME Company is using WPA2-Personal to secure IoT devices that are not capable of 802.1X/EAP authentication. Because an employee was recently fired, all of the company wireless IoT devices and APs had to be reconfigured with a new static 64-bit PSK.
What type of WLAN security solution may have avoided this administrative headache?
- A . MAC filter
- B . Hidden SSID
- C . Changing the default settings
- D . Per-device, per-user PSK
What advantages does using predictive site survey modeling software offer over performing a manual site survey? (Choose 2)
- A . Predictive modeling software can predict the ideal access point location 100% of the time, whereas the results from manual surveying are less reliable.
- B . Predictive modeling software makes it simple to assess multiple different AP locations and then adjust and display the AP’s expected coverage pattern in almost real-time.
- C . Predictive modeling software provides more reliable data than manual surveys when fine-tuning and validating access point placement after the installation.
- D . The exact impact of interference sources from external networks can be more accurately measured when using predictive modeling software than with manual surveys.
- E . It takes less time to create an initial site survey for a large facility when using predictive modeling software than when performing a manual survey.
What is the biggest problem when enabling 5 GHz dynamic frequency selection (DFS) channels?
- A . Channel switch announcements
- B . False positives
- C . Co-channel interference
- D . Adjacent channel interference
- E . The 60-second wait time
What CSMA/CA mechanism is used for medium contention? (Choose all that apply.)
- A . NAV
- B . CCA
- C . Random backoff timer
- D . Contention window
Which technologies debuted in the 802.11ac-2013 amendment? (Choose all that apply.)
- A . MIMO
- B . MU-MIMO
- C . 256-QAM
- D . 40 MHz channels
- E . 80 MHz channels
A single user is complaining that her VoWiFi phone has choppy audio. The WLAN administrator notices that the user’s MAC address has a retry rate of 25 percent when observed with a protocol analyzer.
However, all the other users have a retry rate of about 5 percent when also observed with the protocol analyzer.
What is the most likely cause of this problem?
- A . Near/far
- B . Multipath
- C . Co-channel interference
- D . Hidden node
- E . Low SNR
Your consulting firm has recently been hired to complete a site survey for a company. Your engineers use predictive modeling software for surveying, but the company insists on a predeployment site visit.
What tasks should be performed as part of the pre-deployment visit to prepare for a predictive survey? (Choose 2)
- A . With a spectrum analyzer, identify the type, amplitude, and location of RF interference sources, if any are present.
- B . Evaluate the building materials at ABC’s facility and confirm that the floor plan documents are consistent with the actual building.
- C . Test several antenna types connected to the intended APs for use in the eventual deployment.
- D . Collect information about the company’s security requirements and the current configuration of their RADIUS and user database servers.
- E . Install at least one AP on each side of the exterior walls to test for co-channel interference through these walls.
What security option for 802.11 networks supports SAE and requires protected management frames?
- A . WPA
- B . WPA2
- C . WPA3
- D . OWE
What can cause excessive VSWR in RF cables used to connect a radio to an antenna?
- A . High gain yagi antenna
- B . Radio output power above 100 mW but below 400 mw
- C . High gain parabolic dish antenna
- D . Impedance mismatch
D
Explanation:
Impedance is the measure of opposition to the flow of alternating current (AC) in a circuit. Impedance mismatch occurs when the impedance of the radio does not match the impedance of the antenna or the cable. This causes some of the transmitted or received signal to be reflected back, resulting in a loss of power and efficiency. The voltage standing wave ratio (VSWR) is a metric that indicates the amount of impedance mismatch in a transmission line. A higher VSWR means a higher impedance mismatch and a lower signal quality. A VSWR of 1:1 is ideal, meaning there is no impedance mismatch and no reflected power. A VSWR of 2:1 means that for every 2 units of forward power, there is 1 unit of reflected power12.
The other options are not correct because they do not affect the VSWR in RF cables. A high gain yagi antenna or a high gain parabolic dish antenna can increase the signal strength and directionality, but they do not cause impedance mismatch in the cable. Radio output power above 100 mW but below 400 mW is within the acceptable range for most WLAN devices and does not cause excessive VSWR in the cable3.
Reference: 1: CWNA-109 Official Study Guide, page 77 2: VSWR 3: CWNA-109 Official Study Guide, page 81
What best describes WPA2 in relation to 802.11 wireless networks?
- A . WPA2 is the standard that defines security for WLANs.
- B . WPA2 is a certification created by the Wi-Fi Alliance that validates devices correctly implement CCMP/ AES.
- C . WPA2 is the second version of WPA and it enhances security through the use of TKIP instead of WEP.
- D . WPA2 is specified in the 802.11 standard as implementing CCMP/AES.
B
Explanation:
WPA2 (Wi-Fi Protected Access 2) is a security certification program developed by the Wi-Fi Alliance to secure wireless computer networks.
It is important to understand the following:
WPA2 and the 802.11 Standard: While WPA2 is based on elements of the 802.11i amendment to the 802.11 standard, it is not itself a standard but rather a certification to ensure devices comply with certain security criteria, including the correct implementation of CCMP (Counter Mode Cipher Block Chaining Message Authentication Code Protocol) and AES (Advanced Encryption Standard). CCMP/AES Implementation: WPA2 enhances the security of wireless networks by using CCMP for encryption, which is based on AES, a robust encryption algorithm. This represents a significant security improvement over WEP (Wired Equivalent Privacy) and WPA (Wi-Fi Protected Access) that used TKIP (Temporal Key Integrity Protocol).
WPA vs. WPA2: WPA was the interim security enhancement over WEP, utilizing TKIP for encryption. WPA2, however, moved to the more secure AES-based encryption method. Contrary to option C, WPA2 does not enhance security by using TKIP; it uses CCMP/AES.
Therefore, option B correctly describes WPA2 as a certification program ensuring devices properly implement the more secure CCMP/AES encryption methods.
Reference: Wi-Fi Alliance website for WPA2 certification details.
IEEE 802.11i-2004: Amendment for Enhanced Security.