Practice for the CCNA exam with 23 exam-style practice questions, instant answer reveals, and concise explanations of every correct answer. Topics include: Which characteristic of 802.11a makes it preferable in environments requiring reduced interference and more available ch. Follow @CertPunch and visit certpunch.com for more certification practice exams and study content.
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What you will practice
- Which characteristic of 802.11a makes it preferable in environments requiring reduced interference and more a…
- Two switches have been implemented and all interfaces are at the default configuration level. A trunk link mu…
- What is the default behavior of a Layer 2 switch when a frame with an unknown destination MAC address is rece…
- Which command configures the Cisco WLC to prevent a serial session with the WLC CLI from being automatically…
- Why was the RFC 1918 address space defined?
- What is the purpose of classifying network traffic in QoS?
Answers and explanations
Tap a question to expand the answer and the exam reasoning. Try to commit to your own pick first.
Q1. Which characteristic of 802.11a makes it preferable in environments requiring reduced interference and more available channels?
Answer: D. D. It is used in place of 802.11b/g when many nonoverlapping channels are required
The 802.11a standard operates in the 5 GHz band, providing significantly more non-overlapping channels than 2.4 GHz. The 2.4 GHz band is highly susceptible to interference from common devices like microwaves.
Q2. Two switches have been implemented and all interfaces are at the default configuration level. A trunk link must be implemented between two switches with these requirements: • using an industry-standard trunking protocol • permitting VLANs…
Answer: C. C. switchport mode trunk switchport trunk encapsulation dot1q switchport trunk allowed vlans 1-10
The switchport mode trunk command combined with dot1q encapsulation meets the industry-standard requirement. The trunk allowed vlans command restricts traffic to the specified VLANs, filtering the rest.
Q3. What is the default behavior of a Layer 2 switch when a frame with an unknown destination MAC address is received?
Answer: C. C. The Layer 2 switch floods packets to all ports except the receiving port in the given VLAN.
When a switch receives a frame with an unknown unicast destination MAC, it floods the frame to all ports in the same VLAN except the receiving port. This ensures the frame reaches its intended destination if it exists on the local segment.
Q4. Which command configures the Cisco WLC to prevent a serial session with the WLC CLI from being automatically logged out?
Answer: C. C. config serial timeout 0
The command config serial timeout zero disables the inactivity timeout for the console session on a wireless LAN controller. This configuration prevents the system from automatically logging out a connected serial user.
Q5. Why was the RFC 1918 address space defined?
Answer: A. A. conserve public IPv4 addressing
RFC 1918 defined private IPv4 address ranges to conserve public IPv4 addressing. By allowing organizations to reuse internal addresses that are not routed on the internet, global public IPv4 consumption was significantly reduced.
Q6. What is the purpose of classifying network traffic in QoS?
Answer: C. C. identifies the type of traffic that will receive a particular treatment
The purpose of classifying network traffic in Quality of Service is to identify the type of traffic so that it can receive the appropriate treatment like priority queuing. The distractors incorrectly describe the subsequent steps of matching, servicing, and marking.
Q7. An email user has been lured into clicking a link in an email sent by their company's security organization. The webpage that opens reports that it was safe, but the link may have contained malicious code. Which type of security program is…
Answer: A. A. user awareness
This scenario describes a user awareness program where the company intentionally sends simulated phishing links. These programs are designed to train employees to recognize potentially malicious emails and improve security behavior without causing real harm.
Q8. Which type of cable is typically used to connect a switch to a router Ethernet interface (without auto-MDIX)?
Answer: B. B. Straight-through
A router Ethernet port and a switch port traditionally use opposite transmit and receive pin pairs. Therefore, a straight-through cable is required to connect them when automatic medium-dependent interface crossover is not in play.
Q9. Which concern is addressed with the use of private IPv4 addressing?
Answer: D. D. Lack of available publicly routable unique IPv4 address
Private IPv4 addressing was defined to solve the shortage of publicly routable unique IPv4 addresses. By allowing internal address reuse, organizations conserve their limited public IP space. Options mentioning IPv5 or security protocols are invalid distractors.
Q10. What is a feature of WPA?
Answer: A. A. TKIP/MIC encryption
Temporal Key Integrity Protocol and Message Integrity Check encryption are core features of WPA, designed to replace vulnerable WEP encryption. Preshared keys are a WPA mode, not a structural feature, while eighty-two point one x applies to enterprise security.
Q11. An engineer must establish a trunk link between two switches. The neighboring switch is set to trunk or desirable mode. What action should be taken?
Answer: C. C. configure switchport mode dynamic auto
Configuring switchport mode dynamic auto allows a switch port to become a trunk if the neighboring switch is actively set to trunk or desirable mode. Dynamic auto will never actively initiate trunk negotiations, relying entirely on the neighbor to start the process.
Q12. What is a characteristic of Link Aggregation (LAG) operation on a Cisco Wireless LAN Controller?
Answer: D. D. One functional physical port is needed to pass client traffic.
When link aggregation is enabled on a wireless controller, only one functional physical port is required to pass client traffic. The other options present strict configuration requirements or bandwidth limitations that do not exist.
Q13. Which IPsec mode encrypts only the payload while leaving the original IP header (source and destination IP addresses) unencrypted?
Answer: C. C. Transport
IPsec transport mode encrypts only the payload of an IP packet, leaving the original header intact. Tunnel mode encapsulates the entire original packet and adds a new IP header.
Q14. What is a practice that protects a network from VLAN hopping attacks?
Answer: C. C. Assign all access ports to VLANs other than the native VLAN
Placing access ports in a voice or data VLAN separate from the native VLAN mitigates double-tagged VLAN hopping attacks. Dynamic ARP inspection specifically prevents spoofing attacks rather than VLAN hopping manipulations.
Q15. Which command enables all access ports connected to end devices to enter the forwarding state immediately?
Answer: A. A. switch(config)#spanning-tree portfast default
The spanning-tree portfast default command globally enables PortFast on all access ports, allowing them to bypass listening and learning states. Option B only configures BPDU Guard, while the interface-level commands in C and D do not apply the global setting required.
Q16. PC1 tries to send traffic to newly installed PC2. The PC2 MAC address is not listed in the MAC address table of the switch, so the switch sends the packet to all ports in the same VLAN. Which switching concept does this describe?
Answer: A. A. frame flooding
When a switch receives a frame with an unknown destination MAC address, it forwards that frame out all ports within the same VLAN except the receiving port. This process is known as unknown unicast flooding, or simply frame flooding.
Q17. How does a switch perform MAC address learning?
Answer: A. A. It records the source MAC address of incoming frames and associates it with the ingress port.
A switch dynamically builds its MAC address table by examining the source MAC address of incoming frames. It then maps that source address to the specific ingress port, allowing the switch to intelligently forward future traffic.
Q18. Which security method is used to prevent man-in-the-middle attacks?
Answer: A. A. authentication
Authentication verifies the identity of communicating parties, preventing attackers from successfully impersonating a legitimate endpoint in a man-in-the-middle attack. Authorization, anti-replay, and accounting are secondary controls that assume identity has already been established.
Q19. What can prevent a workstation from receiving a DHCP address during initial network connection?
Answer: A. A. STP
Spanning Tree Protocol can delay a workstation from receiving a DHCP address while a switch port transitions through listening and learning states. Configuring PortFast on access ports bypasses this delay.
Q20. What event has occurred if a router sends a notice level message to a syslog server?
Answer: B. B. An interface line has changed status
Syslog notice level corresponds to severity level five, which typically captures significant but normal operational events like an interface line changing status. Lower severity numbers denote more critical system emergencies that require immediate administrative intervention.
Q21. Which protocol is commonly used as a southbound interface to push configuration changes to network devices over SSH?
Answer: A. A. NETCONF
NETCONF is a network management protocol that uses remote procedure calls to push configuration changes over a secure SSH session. RESTCONF would be the alternative option, but it operates over standard HTTP methods instead of SSH.
Q22. Which signal frequency appears 60 times per minute?
Answer: A. A. 1 Hz signal
A one hertz signal completes one cycle per second, resulting in exactly sixty cycles over a full minute. Higher frequencies complete millions or billions of cycles, making them incorrect for this basic networking math concept.
Q23. In what way does a network supervisor reduce maintenance costs while maintaining network integrity on a traditionally managed network?
Answer: C. C. They use automation to centralize network-management tasks.
Using automation to centralize traditional network-management tasks drastically reduces repetitive manual configurations and minimizes human error. Simply installing monitoring software or adding personnel does not inherently streamline the actual maintenance operations.
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