2025年08月実際に出るCWAP-404試験問題集には正確で更新された問題 [Q58-Q81]

2025年08月実際に出るCWAP-404試験問題集には正確で更新された問題

CWAP-404試験問題集でPDF問題とテストエンジン

質問 # 58
When performing protocol analysis, you capture an 802.11ac data frame on channel 52, transmitted at MSC 8.
At what data rate was the PHY Preamble transmitted?

A. 78 Mbps
B. 54 Mbps
C. 86.7 Mbps
D. 6 Mbps

正解：D

解説：
The transmitter sends the preamble at 1 Mbps (802.11 or 802.11b DSSS) or 6 Mbps (802.11a or
802.11g ERP-OFDM).
Reference: http://mediA.techtarget.com/searchMobileComputing/downloads/CWAP_ch8.pdf

質問 # 59
When using a commercial WLAN protocol analyzer, you notice that it is listing vendor names for some APs and client STAs.
What is the source of this information?

A. Vendor OUI values
B. DNS name resolution
C. Banner grabbing
D. Broadcast name resolution

正解：A

質問 # 60
You are using the real-time FFT display of a spectrum analyzer. In what domain does this show the RF energy detected in the swept frequencies?

A. Length
B. Phase
C. Time
D. Frequency

正解：B

質問 # 61
During an initial install of a controller-based WLAN, the APs are not locating the WLAN controller.
The controller is two router hops away from the nearest AP. DHCP is not used. When performing a packet trace, you see a DNS response code of 3 targeted at one of the APs.
What is the problem?

A. The authentication to the DNS server failed
B. The DNS server is not authoritative for the domain
C. The controller host record has not been created in the DNS server
D. The router is not forwarding packets to the DNS server

正解：C

質問 # 62
What is an AIFS?

A. A form of aggregation performed at the PLCP sub-layer
B. The shortest period of time a STA can sleep
C. A variable Interframe Space introduced by 802.11e to help prioritize medium access for different Access Categories
D. A medium access method introduced by 802.11n, but never implemented

正解：C

解説：
An AIFS is a variable interframe space introduced by 802.11e to help prioritize medium access for different Access Categories (ACs). An interframe space is a period of time that a STA (station) has to wait before attempting to access the medium. An AIFS is a type of interframe space that varies depending on the AC of the traffic. An AC is a logical queue that corresponds to a QoS (Quality of Service) level for different types of traffic. There are four ACs defined by 802.11e:
AC_VO (Voice), AC_VI (Video), AC_BE (Best Effort), and AC_BK (Background). Each AC has a different AIFSN (Arbitration Interframe Space Number) value, which determines how long it has to wait before attempting to access the medium. A lower AIFSN value means a higher priority and a shorter waiting time. The other options are not correct, as they do not describe what an AIFS is.
An AIFS is not a medium access method introduced by 802.11n, but never implemented, as it is part of the 802.11e standard and widely used in QoS-enabled WLANs. An AIFS is not a form of aggregation performed at the PHY layer based on 802.11e UP values interpreted from DSCP values, as aggregation is a technique that combines multiple frames into one larger frame to improve efficiency and throughput, not prioritization or medium access. An AIFS is not the shortest period of time a STA can sleep, as sleeping is a power saving mode that allows a STA to conserve battery power by periodically turning off its radio, not accessing the medium.

質問 # 63
Given: The Frame Check Sequence (FCS) is a 32 CRC used for error detection. The CRC is calculated over what?

A. PHY Header and MAC Header only
B. PHY Header, MAC Header and Frame Body
C. Mac Header and Frame Body only
D. Frame Body only

正解：C

解説：
The CRC is calculated over the MAC Header and Frame Body only. The CRC (Cyclic Redundancy Check) is a 32-bit value that is used for error detection in wireless transmissions.
The CRC is calculated over the MAC Header and Frame Body of a PSDU, which are the parts of the data unit that contain information such as source and destination addresses, frame type, frame control, sequence number, payload, etc. The CRC is appended to the end of the PSDU as a FCS (Frame Check Sequence) field. The CRC is not calculated over the PHY Header or PHY Preamble, which are parts of the PPDU that contain information such as modulation, coding, data rate, etc. The PHY Header and PHY Preamble are added or removed by the PHY layer during the conversion between PSDU and PPDU.

質問 # 64
A client is operating in an unstable RF environment. Out of five data frames transmitted to the client it only receives four. The client sends a Block Ack to acknowledge the receipt of these four frames but due to frame corruption the Block Ack is not received by the AP. Which frames will be transmitted?

A. Both the corrupted data and Block Ack
B. Only the Block Ack
C. Only the data frame which was corrupted
D. All data frames

正解：D

解説：
All data frames will be retransmitted in this scenario. This is because the AP uses a Block Ack (BA) mechanism to acknowledge the receipt of multiple data frames from a client in a single frame. The BA contains a bitmap that indicates which data frames were received correctly and which were not. If the BA is not received by the AP due to frame corruption, the AP will assume that none of the data frames were received by the client and will retransmit all of them. The other options are not correct, as they do not account for the loss of the BA or the use of the bitmap.

質問 # 65
You are performing 802.3 network analysis. For what are the DA and SA fields used in the frame header?

A. They are not used; addresses are only used in the 802.11 header
B. Defining either distance access routing or strict access routing
C. Defining either direct access or sourced access
D. Defining the addresses sending and receiving the frame

正解：D

質問 # 66
What is the function of the PHY layer?

A. Convert PSDUs to PPDUs for transmissions and PPDUs to PSDUs for receptions
B. Convert PPDUs to PSDUs for transmissions and PSDUs to PPDUs for receptions
C. Convert MSDUs to PPDUs for transmissions and PPDUs to MSDUs for receptions
D. Convert PPDUs to MSDUs for transmissions and MSDUs to PPDUs for receptions

正解：A

解説：
Explanation
The function of the PHY layer is to convert PSDUs to PPDUs for transmissions and PPDUs to PSDUs for receptions. A PSDU (PHY Service Data Unit) is the data unit that is passed from the MAC layer to the PHY layer for transmission, or from the PHY layer to the MAC layer for reception. A PPDU (PHY Protocol Data Unit) is the data unit that is transmitted or received over the wireless medium by the PHY layer. A PPDU consists of a PSDU and a PHY header, which contains information such as modulation, coding, and data rate.
The PHY layer adds or removes the PHY header to or from the PSDU during the conversion process. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 4: 802.11 Physical Layer, page 97-98

質問 # 67
Recently, three rogue APs have been connected to the network and later discovered. You want to prevent future rogue AP installations as much as possible.
What is the first step to eliminating or reducing rogue APs on the network?

A. Create a hash of the MAC addresses of all authorized devices and continually scan for non- matching hashes
B. Enable rogue detection in the existing authorized APs
C. Use IPSec between every AP and the network infrastructure
D. Define a direct policy that stipulates the ramifications of installing unauthorized devices

正解：B

質問 # 68
The manager in the security group is concerned about compliance with security policies on the WLAN. The budget is not available for a full WIPS SOLUTION. He has asked you to implement a process that will verify compliance.
What would you recommend in such a scenario?

A. Use a laptop-based protocol analyzer that provides compliance reporting to monitor the environment on a periodic basis
B. Implement AP-based sensors throughout the facility and then monitor for performance issues with these sensors
C. Use the built-in spectrum analyzer features of the APs to ensure that WPA2-Enterprise is implemented throughout the organization
D. Simplify enable 802.11w, which will enforce management frame compliance

正解：A

質問 # 69
Finish the statement:
It is possible to distinguish between_______22 MHz transmissions and________20 MHz transmissions when looking at an FFT plot.

A. HT and VHT
B. ERP and VHT
C. HR/DSSS and ERP
D. OFDM and HT

正解：D

解説：
Explanation
It is possible to distinguish between OFDM 20 MHz transmissions and HT 20 MHz transmissions when looking at an FFT plot. OFDM and HT are two different modulation schemes used by 802.11 WLANs. OFDM is used by legacy 802.11a/g devices, while HT is used by newer 802.11n/ac devices. OFDM and HT have different spectral characteristics that can be observed on an FFT plot. OFDM transmissions have a flat spectrum with sharp edges, while HT transmissions have a tapered spectrum with rounded edges. This is because HT uses guard intervals and cyclic prefixes to reduce inter-symbol interference and improve performance. The other options are not correct, as they do not describe different modulation schemes or channel widths that can be distinguished on an FFT plot. References: [Wireless Analysis Professional Study Guide CWAP-404], Chapter 3: Spectrum Analysis, page 70-71

質問 # 70
Which statement is true regarding the Association Identifier (AID) used in IEEE 802.11 WLANs?

A. The AID has a maximum value of 2048, and is used to uniquely identify a wireless client station associated with an access point.
B. The AID is used by the access point in EDCA mode to reduce duplicate transmissions when sending multicasts.
C. The client station is assigned an AID value in the 802.11 authentication response frame.
D. The AID has a maximum value of 2007, and resides in the duration/ID field of a PS-Poll frame.
E. The AID field is present only in Beacons frames.

正解：D

質問 # 71
What should the To DS and From DS flags be to set to in an Association Response frame?

A. To DS = 0, From DS = 1
B. To DS = 0, From DS = 0
C. To DS = 1, From DS = 0
D. To DS = 1, From DS = 1

正解：A

解説：
The To DS and From DS flags should be set to 0 in an Association Response frame. An Association Response frame is a type of management frame that is transmitted by an AP to accept or reject an association request from a STA. The To DS (To Distribution System) and From DS (From Distribution System) flags are two bits in the Frame Control field of the MAC header that indicate whether a frame is destined for or originated from the DS (Distribution System), which is a system that connects multiple BSSs together. The To DS and From DS flags can have four possible combinations: 00, 01, 10, or 11. For an Association Response frame, which is sent from an AP to a STA within a BSS, both flags should be set to 0.

質問 # 72
What two IEEE 802.11 entities may be used to separate successful transmissions within an EDCA TXOP? (Choose 2)

A. SIFS
B. RIFS
C. PIFS
D. AIFS
E. EIFS
F. CAP
G. ACK

正解：A、B

質問 # 73
You have been recently hired as the wireless network administrator for an organization spread across seven locations. They have deployed more than 100 APs, but they have not been managed in either an automated or manual process for more than 18 months.
Given this length of time, what is one of the first things you should evaluate from a support perspective?

A. The channels in use
B. The VLANs in use
C. The firmware revision
D. The data rates allowed

正解：C

質問 # 74
You are performing a multiple adapter channel aggregation capture to troubleshoot a VoIP roaming problem and would like to measure the roaming time from the last VoIP packet sent on the old AP's channel to the first VoIP packet sent on the new AP's channel. Which timing column in the packet view would measure this for you?

A. Delta
B. Relative
C. Absolute
D. Roaming

正解：A

解説：
Explanation
Delta is the timing column in the packet view that measures the time difference between two consecutive packets in a capture file. Delta can be used to measure the roaming time from the last VoIP packet sent on the old AP's channel to the first VoIP packet sent on the new AP's channel by selecting these two packets and looking at their delta values. The other timing columns are not suitable for this measurement because they do not show the time difference between two specific packets. Roaming is a column that shows whether a packet belongs to a roaming event or not. Relative is a column that shows the time elapsed since the beginning of the capture file. Absolute is a column that shows the date and time when a packet was captured5 References:
CWAP-404 Study Guide, Chapter 2: Protocol Analysis, page 57
CWAP-404 Objectives, Section 2.4: Analyze timing values

質問 # 75
What is used to respond with an uplink transmission to an MU-RTS trigger frame in the 802.11ax PHY?

A. HE SU PPDU
B. HE MU PPDU
C. VHT PPDU
D. HE TB PPDU

正解：D

解説：
An HE TB PPDU (High Efficiency Trigger-Based Packet Data Unit) is used to respond with an uplink transmission to an MU-RTS trigger frame in the 802.11ax PHY (Physical Layer). An MU- RTS trigger frame is a frame that initiates a multi-user transmission opportunity (MU-TXOP) by requesting multiple stations (STAs) to send clear-to-send (CTS) frames on different spatial streams or resource units (RUs). An HE TB PPDU is a frame that contains data from multiple STAs that have been allocated RUs by an MU-RTS trigger frame or another type of trigger frame.
An HE SU PPDU (High Efficiency Single User Packet Data Unit) is a frame that contains data from a single STA using all available spatial streams or RUs. An HE MU PPDU (High Efficiency Multi User Packet Data Unit) is a frame that contains data from multiple STAs using different spatial streams or RUs without being triggered by another frame. A VHT PPDU (Very High Throughput Packet Data Unit) is a frame that uses the 802.11ac PHY and does not support multi- user transmissions.

質問 # 76
ABC Company requires the ability to identify and quickly locate rogue devices. ABC has chosen an overlay WIPS solution with Wi-Fi sensors that use dipole antennas to perform this task. No other sensors are included. Use your knowledge of location tracking techniques to answer the question.
Which one of the following location methods is not available in the described system?

A. GPS Positioning
B. RF Fingerprinting
C. Trilateration of RSSI measurements
D. Time Difference of Arrival (TDoA)

正解：A

質問 # 77
What is the Extended IFS used in 802.11 contention?

A. When the lower data rates are used and you want the fastest medium access times
B. When 802.11ac must coexist with 802.11n
C. When the higher data rates are used and you want the fastest medium access times
D. When a frame reception begins but the received frame is incomplete or corrupted based on the FCS

正解：B

質問 # 78
When performing protocol analysis, you notice a high number of RTS/CTS frames being transmitted on an HT network. You suspect this may be due to HT protection mechanisms.
Where in the Beacon frame would you look to determine which one of the four HT protection modes the AP is operating in?

A. HT Operation Element
B. HT Information Element
C. HT Protection Element
D. Non-HT Present Element

正解：B

解説：
When performing protocol analysis, you would look at the HT Information Element in the Beacon frame to determine which one of the four HT protection modes the AP is operating in. The HT Information Element contains various subfields that provide information about the HT network configuration and operation. One of these subfields is the HT Protection field, which indicates whether any protection mechanisms are required for mixed-mode operation with non-HT STAs.
The four possible values for this field are:
No Protection: No protection mechanisms are required.
Non-member Protection: RTS/CTS or CTS-to-self protection is required for all HT transmissions.
20 MHz Protection: RTS/CTS or CTS-to-self protection is required for all HT transmissions using a 40 MHz channel.
Non-HT Mixed Mode: All HT transmissions must use a non-HT preamble and header.

質問 # 79
A manager at a retail outlet has complained that an incident occurred allowing a STA to launch an attack against another STA connected to their public Wi-Fi hotspot. He has asked you to troubleshoot the situation and verify that all possible measured are being taken to prevent this.
What configuration should you check in the AP?

A. Client-to-client direct communications
B. Inter-VAP filtering
C. Captive portal Internet gateway
D. DNS settings

正解：A

解説：
Disabling client-to-client communication (also known as peer-to-peer or "AP isolation") prevents devices connected to the same wireless network from communicating directly with each other.
This helps mitigate attacks where one client station (STA) could attack another STA, such as through ARP spoofing or other local network-based attacks.

質問 # 80
While troubleshooting DHCP issues, you perform a protocol capture in order to determine if the DNCP pool is depleted. The capture does not show DHCPnak messages. Where else could you look to determine if the pool is depleted?