CompTIA  N10-009  Network+  Exam Dumps and Practice Test Questions Set 7 Q121-140

Visit here for our full CompTIA N10-009 exam dumps and practice test questions.

Question 121

A network administrator wants to segment a network into smaller broadcast domains to improve performance and security. Which technology should be deployed?

A) VLANs
B) LACP
C) STP
D) Port security

Answer: A) VLANs

Explanation:

A) VLANs, or Virtual Local Area Networks, logically segment a single physical network into multiple broadcast domains. Each VLAN isolates traffic within its domain, ensuring that broadcast traffic from one VLAN does not overwhelm devices in another VLAN. This segmentation reduces unnecessary traffic, improves overall network performance, and enhances security by preventing unauthorized access between segments unless explicitly routed through Layer 3 devices. VLANs also enable network administrators to group users based on roles, departments, or security levels without requiring physical separation of the infrastructure. This logical separation simplifies network management, makes troubleshooting more straightforward, and allows for better implementation of policies such as Quality of Service (QoS) and access control lists. VLANs operate at the data-link layer, but they can interact with Layer 3 routing for inter-VLAN communication, providing both isolation and controlled connectivity. They are essential in enterprise environments to manage congestion, improve security, and maintain operational efficiency.

B) LACP (Link Aggregation Control Protocol) combines multiple physical links into a single logical link to increase bandwidth and provide redundancy. While LACP enhances throughput and fault tolerance, it does not segment a network into smaller broadcast domains. Its primary function is to optimize link-level performance rather than isolate traffic or improve Layer 2 efficiency.

C) STP (Spanning Tree Protocol) prevents loops in Layer 2 networks by selectively blocking redundant paths. While critical for network stability, STP does not segment traffic or create broadcast domains. It ensures loop-free topology but does not reduce broadcast congestion or enforce security boundaries between groups of devices.

D) Port security limits access to switch ports based on MAC addresses, preventing unauthorized devices from connecting to the network. While it enhances endpoint security, it does not provide logical segmentation or reduce broadcast domains. Port security controls access but does not manage traffic flow or optimize performance across multiple devices.

VLANs are the only technology that provides logical segmentation of networks, isolates broadcast traffic, enhances security, and improves network performance, making them the correct choice.

Question 122

A network engineer wants to provide secure encrypted communication for employees accessing internal resources remotely. Which solution should be implemented?

A) Remote VPN
B) Public Wi-Fi
C) Static routing
D) NAT

Answer: A) Remote VPN

Explanation:

A) Remote VPN (Virtual Private Network) establishes a secure encrypted tunnel between a remote client and the corporate network over an untrusted network such as the Internet. VPNs ensure confidentiality, integrity, and authentication of data, allowing employees to securely access internal resources like file servers, intranet sites, and email systems. They typically use tunneling protocols such as IPsec, SSL/TLS, or L2TP to encapsulate traffic, preventing interception or tampering. Remote VPN solutions often include multi-factor authentication, certificate-based access, and endpoint verification to ensure that only authorized users and devices connect. They also support centralized management for monitoring, logging, and policy enforcement, providing scalability for large organizations. VPNs are essential for remote work, allowing employees to maintain productivity without exposing sensitive corporate data to potential threats on public networks. By encrypting all traffic between the remote endpoint and the corporate network, VPNs mitigate risks such as man-in-the-middle attacks and eavesdropping.

B) Public Wi-Fi provides internet connectivity but is inherently untrusted and insecure. Without encryption or authentication, data transmitted over public Wi-Fi can be intercepted, modified, or captured by attackers. Public Wi-Fi alone cannot provide secure access to corporate resources and exposes sensitive information to significant risk.

C) Static routing defines predetermined paths for traffic within a network. While useful for internal traffic management, static routing does not provide encryption, authentication, or secure connectivity over untrusted networks. It cannot protect remote communication, making it unsuitable for secure remote access.

D) NAT (Network Address Translation) allows private IP addresses to communicate with external networks by translating them to public IP addresses. While NAT facilitates connectivity, it does not encrypt traffic or authenticate users. NAT alone does not protect sensitive data in transit or provide secure remote access.

A remote VPN provides encrypted, authenticated, and secure access to internal resources over the Internet, making it the correct choice.

Question 123

A technician wants to prevent unauthorized devices from connecting to the network while allowing legitimate devices to move between ports without manual configuration. Which solution is appropriate?

A) Port security with sticky MAC addresses
B) VLAN trunking
C) STP
D) DHCP snooping

Answer: A) Port security with sticky MAC addresses

Explanation:

A) Port security with sticky MAC addresses allows a switch to dynamically learn and store the MAC addresses of devices connected to a port. Authorized devices can move between ports and be automatically recognized without requiring manual configuration. If an unauthorized device attempts to connect, the switch can take actions such as shutting down the port, blocking traffic, or generating an alert. This feature provides strong endpoint security while maintaining operational flexibility. Sticky MAC addresses work well in dynamic environments where devices frequently change ports, as it reduces administrative overhead and prevents rogue devices from gaining access. It can also be combined with DHCP snooping and Dynamic ARP Inspection to enhance overall network security. By enforcing device-based authentication at the port level, sticky MAC addresses help maintain both security and ease of network management.

B) VLAN trunking allows multiple VLANs to share a single link between switches. While trunking enables efficient transport of segmented traffic, it does not authenticate devices or prevent unauthorized access. VLAN trunking addresses traffic segmentation but does not enforce endpoint-level security.

C) STP (Spanning Tree Protocol) prevents loops in Layer 2 networks. While critical for topology stability, it does not authenticate devices or prevent unauthorized access. STP manages redundant paths but cannot enforce port-level security.

D) DHCP snooping validates DHCP server responses to prevent rogue IP assignments. While important for IP security, DHCP snooping does not control all network traffic or prevent unauthorized devices from connecting to a port. It is limited to DHCP messages, so it cannot fully meet the requirement.

Port security with sticky MAC addresses provides dynamic validation, allows legitimate device mobility, and blocks unauthorized access, making it the correct choice.

Question 124

A network administrator wants to forward multicast traffic only to devices requesting it to reduce unnecessary network load. Which feature should be enabled?

A) IGMP snooping
B) VLAN trunking
C) STP
D) DHCP snooping

Answer: A) IGMP snooping

Explanation:

A) IGMP snooping monitors IGMP messages between hosts and multicast routers to determine which devices have joined specific multicast groups. By listening to join and leave requests, switches forward multicast traffic only to ports with interested devices. This prevents flooding multicast traffic to all ports, reducing unnecessary bandwidth consumption and improving overall network performance. IGMP snooping is crucial in environments with IPTV, video streaming, or other multicast-heavy applications. It maintains a dynamic forwarding table, ensuring efficient delivery to only requesting devices. By reducing congestion and unnecessary traffic, IGMP snooping helps maintain the quality of service for latency-sensitive applications and ensures that multicast communication is delivered efficiently without affecting other network operations.

B) VLAN trunking allows multiple VLANs to be transported over a single link. While trunking supports traffic segmentation, it does not analyze multicast group membership or prevent flooding. Trunking alone cannot selectively forward multicast traffic.

C) STP prevents loops in Layer 2 networks. While important for topology stability, STP does not control multicast delivery. It manages redundant paths but has no mechanism to optimize multicast traffic forwarding.

D) DHCP snooping validates DHCP messages from trusted servers. While securing IP allocation, DHCP snooping does not manage multicast traffic or selectively forward it to requesting devices. Its functionality is limited to DHCP traffic.

IGMP snooping ensures multicast traffic is delivered only to requesting devices, reducing congestion and optimizing network efficiency, making it the correct choice.

 

Question 125

A technician needs to measure throughput, jitter, and packet loss between two endpoints to troubleshoot VoIP quality issues. Which tool should be used?

A) iPerf
B) Netstat
C) ARP
D) Traceroute

Answer: A) iPerf

Explanation:

A) iPerf is a network performance testing tool that measures critical metrics like throughput, jitter, latency, and packet loss between two endpoints. These metrics are essential for troubleshooting VoIP and other real-time applications that require low latency and consistent delivery. iPerf generates controlled traffic streams using TCP or UDP protocols, allowing administrators to simulate real-world network conditions. It provides configurable parameters such as test duration, parallel streams, and window size to analyze performance under different scenarios. By using a client-server setup, iPerf enables engineers to identify bottlenecks, optimize routing, configure quality-of-service policies, and validate whether the network can support VoIP traffic with acceptable quality. iPerf is widely used in enterprise and service provider environments because it provides precise, repeatable, and actionable performance data. It allows administrators to proactively detect issues before they impact users and ensures that latency-sensitive applications operate efficiently.

B) Netstat shows active connections, listening ports, and routing information on a host. While useful for monitoring current sessions, it does not generate test traffic or measure throughput, jitter, or packet loss. Netstat cannot provide detailed performance data required for VoIP troubleshooting.

C) ARP resolves IP addresses to MAC addresses on a local network. ARP operates at the link layer and is used for device identification. It does not measure performance metrics or simulate traffic, making it unsuitable for evaluating VoIP quality.

D) Traceroute identifies the path packets take between two devices and measures per-hop latency. While it can detect routing delays, it does not measure throughput, jitter, or packet loss under load conditions. Traceroute provides limited insight into network performance and is not adequate for VoIP troubleshooting.

iPerf is the only tool that provides accurate, measurable throughput, jitter, and packet loss data for performance analysis, making it the correct choice.

Question 126

A network administrator wants to combine multiple physical links between two switches to increase bandwidth and provide redundancy. Which protocol should be implemented?

A) Link Aggregation Control Protocol (LACP)
B) VLAN
C) STP
D) Port security

Answer: A) Link Aggregation Control Protocol (LACP)

Explanation:

A) LACP is a protocol used to combine multiple physical links into a single logical connection between network devices. This aggregation increases bandwidth by distributing traffic across all member links, improving throughput for high-demand applications such as server uplinks, backbone connections, or inter-switch links. Additionally, LACP provides redundancy: if one physical link fails, the remaining links continue to carry traffic without interruption. LACP negotiates compatible links between devices dynamically, ensuring that misconfigurations are minimized and all aggregated links function properly. Load-balancing algorithms are used to distribute traffic efficiently across the links based on MAC addresses, IP addresses, or sessions. By logically combining multiple links, LACP maximizes the use of available physical bandwidth, enhances network resiliency, and allows organizations to scale their network infrastructure without adding single points of failure. In enterprise environments and data centers, LACP is widely deployed to ensure both performance optimization and high availability.

B) VLANs segment a network into multiple logical broadcast domains to reduce congestion and improve security. While VLANs improve network management and isolation, they do not aggregate physical links or increase bandwidth. VLANs address traffic isolation rather than link-level performance, making them unsuitable for combining multiple links.

C) STP (Spanning Tree Protocol) prevents loops in Layer 2 networks by selectively blocking redundant paths. While critical for maintaining a loop-free topology, STP does not increase link capacity. In fact, STP may block links that could otherwise be used for traffic, which is opposite to the goal of bandwidth aggregation.

D) Port security restricts access to switch ports based on MAC addresses to prevent unauthorized devices from connecting. While it provides endpoint-level security, it does not increase bandwidth, combine physical links, or provide redundancy. Port security addresses access control, not link performance or redundancy.

LACP is the only protocol that provides both increased bandwidth and redundancy between switches while dynamically managing aggregated links, making it the correct choice.

Question 127

A network engineer wants to capture traffic from specific switch ports to analyze network issues without interrupting operations. Which feature should be used?

A) SPAN/mirror port
B) VLAN trunking
C) STP
D) DHCP snooping

Answer: A) SPAN/mirror port

Explanation:

A) SPAN (Switched Port Analyzer) or mirror port allows a switch to replicate traffic from one or more source ports or VLANs to a designated monitoring port. This enables network administrators to analyze traffic using tools such as Wireshark without impacting network operations. SPAN is particularly valuable for troubleshooting performance issues, detecting anomalies, monitoring packet flows, and identifying misconfigurations. It supports multiple source ports or VLANs, offering flexibility in complex network environments. By passively duplicating traffic, SPAN ensures the network continues to function normally while providing visibility into packet contents. Administrators can measure latency, packet loss, throughput, or abnormal traffic patterns, which is critical for performance optimization and proactive issue resolution. SPAN is widely used in enterprise networks to maintain operational continuity while performing detailed traffic analysis.

B) VLAN trunking allows multiple VLANs to share a single link between switches. While essential for transporting VLAN traffic, trunking does not provide the ability to duplicate or analyze traffic. It focuses on traffic delivery between VLANs, not traffic visibility or troubleshooting.

C) STP prevents loops in Layer 2 networks by selectively blocking redundant paths. While necessary for stability, STP does not provide traffic replication for monitoring purposes. It manages topology but offers no insight into packet contents or network performance.

D) DHCP snooping validates DHCP server responses to prevent rogue IP assignments. While important for IP security, it does not allow network-wide traffic monitoring or capture. Its functionality is limited to DHCP messages and cannot provide performance or troubleshooting visibility for general traffic.

SPAN/mirror ports are specifically designed for traffic monitoring and analysis without disrupting operations, making them the correct choice.

Question 128

A network engineer wants to reduce wireless interference and improve throughput in a high-density office environment. Which action is most effective?

A) Move clients to the 5 GHz band
B) Increase DHCP lease time
C) Enable Telnet on the access point
D) Reduce MTU size

Answer: A) Move clients to the 5 GHz band

Explanation:

A) Moving clients to the 5 GHz band reduces interference and improves throughput in high-density environments. The 2.4 GHz band is heavily used by Wi-Fi networks, Bluetooth devices, and other electronics, causing co-channel and adjacent-channel interference. The 5 GHz band provides more non-overlapping channels, higher data rates, and less congestion, allowing better performance for applications such as VoIP, video conferencing, and large file transfers. Although 5 GHz has a shorter range than 2.4 GHz due to higher frequency attenuation, careful placement of access points ensures adequate coverage. Moving clients to 5 GHz also allows for better channel reuse and reduces collisions, which is crucial in offices with many devices. Proper planning and channel allocation can maximize the performance benefits of 5 GHz, improving reliability and user experience.

B) Increasing DHCP lease time reduces how frequently devices request IP addresses but does not address wireless interference or congestion. It affects IP address management, not RF performance, and will not improve throughput.

C) Enabling Telnet on an access point allows remote administration but has no effect on interference or client throughput. Management protocols do not optimize RF conditions or bandwidth utilization.

D) Reducing MTU size changes the maximum packet size, which may reduce fragmentation in some scenarios. However, it does not address wireless interference or network congestion and will not significantly improve throughput in a high-density environment.

Moving clients to the 5 GHz band directly reduces interference, increases available channels, and improves throughput, making it the correct choice.

Question 129

A technician wants to prevent unauthorized devices from connecting to the network while allowing legitimate devices to move between ports. Which solution should be used?

A) Port security with sticky MAC addresses
B) VLAN trunking
C) STP
D) DHCP snooping

Answer: A) Port security with sticky MAC addresses

Explanation:

A) Port security with sticky MAC addresses allows a switch to dynamically learn MAC addresses of devices connected to a port and store them in the running configuration. Authorized devices can move between ports without requiring manual configuration, while unauthorized devices attempting to connect can be blocked, shut down, or generate an alert. Sticky MAC addresses provide strong endpoint-level security, reduce administrative overhead, and prevent unauthorized access while maintaining operational flexibility. This solution is particularly effective in dynamic environments where devices frequently change ports. Port security with sticky MAC addresses also integrates well with other security features such as DHCP snooping and Dynamic ARP Inspection, providing a layered approach to network protection.

B) VLAN trunking allows multiple VLANs to share a single physical link between switches. While trunking enables logical traffic segmentation, it does not prevent unauthorized devices from connecting. VLAN trunking addresses traffic transport, not endpoint authentication.

C) STP prevents loops in Layer 2 networks by blocking redundant paths. While essential for topology stability, STP does not control which devices can access the network or enforce endpoint-level security.

D) DHCP snooping validates DHCP messages from trusted servers and blocks rogue IP assignments. While it prevents unauthorized IP assignment, it does not enforce device-level access control on a switch port, so it cannot fully prevent unauthorized network connections.

Port security with sticky MAC addresses provides dynamic device validation, blocks unauthorized access, and allows legitimate devices to move between ports, making it the correct choice.

Question 130

A network engineer wants to measure throughput, jitter, and packet loss between two endpoints to troubleshoot VoIP performance issues. Which tool should be used?

A) iPerf
B) Netstat
C) ARP
D) Traceroute

Answer: A) iPerf

Explanation:

A) iPerf is a performance testing tool used to measure network throughput, jitter, latency, and packet loss between two endpoints. These metrics are critical for troubleshooting VoIP and other real-time applications that require low latency and minimal packet loss. iPerf generates traffic streams over TCP or UDP protocols, allowing administrators to simulate real network conditions and evaluate performance. It provides configurable parameters, including test duration, parallel streams, and window size, to mimic different traffic patterns. Using a client-server setup, iPerf helps identify network bottlenecks, validate quality-of-service policies, and ensure that VoIP traffic can traverse the network without degradation. Its repeatable and precise measurements allow administrators to optimize routing, detect congestion points, and proactively address issues before they impact users. iPerf is widely used in enterprise and service provider networks to evaluate network readiness for latency-sensitive applications, making it an indispensable tool for troubleshooting VoIP performance issues.

B) Netstat displays active network connections, listening ports, and routing tables. While useful for monitoring sessions, it does not measure throughput, jitter, or packet loss, and cannot simulate traffic to assess network performance.

C) ARP resolves IP addresses to MAC addresses on a local network. While essential for communication at Layer 2, ARP does not measure network performance or traffic quality metrics such as jitter or packet loss.

D) Traceroute identifies the path packets take between two devices and measures per-hop latency. While useful for identifying routing issues, it does not provide sustained throughput measurements or detailed packet loss and jitter data required for VoIP troubleshooting.

iPerf is the only tool that generates test traffic and provides accurate, measurable throughput, jitter, and packet loss data, making it the correct choice.

Question 131

A network administrator wants to prevent Layer 2 loops in a network with redundant paths. Which protocol should be implemented?

A) Spanning Tree Protocol (STP)
B) VLAN trunking
C) LACP
D) DHCP snooping

Answer: A) Spanning Tree Protocol (STP)

Explanation:

A) STP is designed to prevent Layer 2 loops in networks with redundant links. When multiple paths exist between switches, frames can circulate endlessly, causing broadcast storms and network outages. STP dynamically identifies redundant paths and selectively places some ports into a blocking state while keeping others in a forwarding state, maintaining a loop-free topology. If a primary path fails, STP recalculates the network topology to unblock a redundant path, ensuring continuous connectivity. This mechanism protects against network degradation caused by loops while still providing redundancy for reliability. STP operates at the data-link layer and can work across VLANs with per-VLAN instances, known as PVST+. By blocking loops without completely removing redundant links, STP maintains fault tolerance and network resilience. It is an essential protocol for stable Layer 2 networks, especially in enterprise environments where uptime is critical.

B) VLAN trunking allows multiple VLANs to share a single physical link between switches. While trunking enables VLAN communication and segmentation, it does not prevent loops or manage redundant paths. Trunking facilitates the transport of multiple broadcast domains but does not offer loop prevention mechanisms.

C) LACP aggregates multiple physical links into a single logical interface to increase bandwidth and provide redundancy. While LACP provides fault tolerance and higher throughput, it does not detect or prevent Layer 2 loops. In fact, without STP, using LACP across redundant paths could contribute to loops in a network.

D) DHCP snooping monitors DHCP messages to prevent unauthorized IP assignments from rogue servers. While it enhances IP security, DHCP snooping does not manage network topology or prevent broadcast storms caused by Layer 2 loops. Its function is limited to DHCP traffic validation.

STP is the only protocol designed to detect and prevent Layer 2 loops while maintaining redundancy, making it the correct choice.

Question 132

 A technician wants to secure a switch port so that only a specific set of devices can connect. Which feature should be implemented?

A) Port security
B) VLAN trunking
C) STP
D) DHCP snooping

Answer: A) Port security

Explanation:

A) Port security restricts access to a switch port based on MAC addresses. Administrators can configure the port to allow only specific devices, preventing unauthorized connections. If an unknown device attempts to connect, the switch can shut down the port, block traffic, or generate an alert. This feature provides a strong security layer, protecting the network from rogue devices and potential attacks. Port security can operate in static mode, where specific MAC addresses are manually configured, or in dynamic mode, where MAC addresses are learned automatically and optionally saved in the configuration (sticky MAC). It is particularly effective in environments such as offices or classrooms, where network access should be limited to approved endpoints. By controlling port access, port security helps maintain network integrity and compliance with security policies.

B) VLAN trunking allows multiple VLANs to be transmitted over a single link between switches. While essential for traffic segmentation and transport, trunking does not restrict which devices can connect to a port or enforce access control. Its focus is on transporting multiple VLANs, not endpoint security.

C) STP prevents Layer 2 loops by selectively blocking redundant links. While critical for network stability, STP does not control access to switch ports or validate connected devices. Its purpose is topology management rather than security.

D) DHCP snooping monitors DHCP traffic to prevent unauthorized IP assignments. While it enhances network security by validating IP assignments, it does not prevent unauthorized devices from connecting to a port or limit access to specific endpoints.

Port security is specifically designed to restrict switch port access to authorized devices, making it the correct choice.

Question 133

A network engineer wants to analyze traffic patterns from specific ports on a switch without affecting normal operations. Which solution is most appropriate?

A) SPAN/mirror port
B) VLAN trunking
C) STP
D) DHCP snooping

Answer: A) SPAN/mirror port

Explanation:

A) SPAN (Switched Port Analyzer) or mirror port duplicates traffic from one or more source ports or VLANs to a designated monitoring port. This allows administrators to capture and analyze traffic using tools like Wireshark without disrupting network operations. SPAN is crucial for troubleshooting latency, packet loss, or misconfigurations in enterprise environments. It supports multiple source ports, enabling comprehensive analysis across critical network segments. SPAN allows detailed visibility into packet flows, helping identify bottlenecks, abnormal traffic patterns, and security incidents. Since it operates passively, SPAN does not affect the transmission of traffic on source ports, ensuring normal operations continue while monitoring is performed. SPAN is widely deployed in enterprise and data center environments to provide accurate, real-time traffic insights without compromising uptime.

B) VLAN trunking transports multiple VLANs across a single link. While necessary for segmenting traffic and inter-VLAN communication, it does not provide a method for capturing traffic for analysis. Trunking is concerned with forwarding traffic rather than monitoring it.

C) STP prevents loops by blocking redundant paths in Layer 2 networks. While essential for stability, it does not provide visibility into traffic or allow traffic capture. STP ensures a loop-free topology but offers no monitoring capabilities.

D) DHCP snooping validates DHCP server responses to prevent rogue IP assignments. While important for IP security, it does not duplicate traffic or allow detailed traffic analysis from specific ports. Its scope is limited to DHCP messages.

SPAN/mirror ports are specifically designed for passive traffic monitoring, making them the correct choice.

Question 134

A network administrator wants to forward multicast traffic only to devices that request it to conserve bandwidth. Which feature should be enabled?

A) IGMP snooping
B) VLAN trunking
C) STP
D) DHCP snooping

Answer: A) IGMP snooping

Explanation:

A) IGMP snooping monitors IGMP messages exchanged between hosts and multicast routers to determine which devices have joined specific multicast groups. By listening to join and leave requests, switches forward multicast traffic only to ports with interested devices. This prevents multicast flooding to all ports, reducing unnecessary bandwidth usage and network congestion. IGMP snooping is critical in environments with IPTV, video streaming, or other multicast-heavy applications. It dynamically maintains a forwarding table for multicast traffic, ensuring that only requesting devices receive the packets. By efficiently delivering multicast traffic, IGMP snooping improves performance, reduces packet loss, and preserves the quality of service for latency-sensitive applications. It also minimizes the impact on unrelated traffic, making multicast communication scalable and efficient in enterprise networks.

B) VLAN trunking allows multiple VLANs to share a single link between switches. While trunking facilitates the transport of segmented traffic, it does not manage multicast group membership or selectively forward multicast traffic. Trunking alone cannot prevent bandwidth waste caused by multicast flooding.

C) STP prevents loops in Layer 2 networks by blocking redundant links. While important for stability, STP does not control multicast delivery. It addresses topology management but cannot optimize traffic forwarding based on group membership.

D) DHCP snooping validates DHCP server responses to prevent unauthorized IP assignment. While enhancing IP security, DHCP snooping does not forward multicast traffic selectively. Its functionality is limited to DHCP traffic and cannot optimize multicast delivery.

IGMP snooping ensures multicast traffic is delivered only to requesting devices, conserving bandwidth and improving performance, making it the correct choice.

Question 135

A network technician wants to measure network throughput, jitter, and packet loss between two endpoints to troubleshoot VoIP issues. Which tool is most appropriate?

A) iPerf
B) Netstat
C) ARP
D) Traceroute

Answer: A) iPerf

Explanation:

A) iPerf is a performance measurement tool that tests network throughput, jitter, latency, and packet loss between two endpoints. These metrics are critical for evaluating VoIP and other real-time applications that require low latency and consistent delivery. iPerf generates traffic streams over TCP or UDP to simulate network conditions and provides configurable parameters such as test duration, parallel streams, and window size. By setting up a client-server connection, administrators can measure throughput under load, detect bottlenecks, and validate network readiness for VoIP traffic. iPerf also helps optimize quality-of-service policies, troubleshoot congestion points, and ensure latency-sensitive applications maintain high performance. Its repeatable, accurate measurements make it an industry-standard tool for network performance testing, allowing proactive detection of network issues and providing detailed insights for troubleshooting VoIP and other time-sensitive applications.

B) Netstat shows active connections, listening ports, and routing tables. While useful for monitoring network sessions, it does not generate test traffic or measure throughput, jitter, or packet loss. It cannot simulate network conditions or provide metrics necessary for VoIP troubleshooting.

C) ARP resolves IP addresses to MAC addresses on a local network. ARP operates at the data-link layer and does not provide information about throughput, latency, or packet loss. It is unsuitable for testing VoIP performance.

D) Traceroute identifies the path packets take between two devices and measures per-hop latency. While helpful for detecting routing issues, it does not measure throughput, jitter, or sustained packet loss under load conditions, making it insufficient for evaluating VoIP performance.

iPerf generates test traffic and provides accurate measurements of throughput, jitter, and packet loss, making it the correct choice.

Question 136

A network administrator wants to allow multiple VLANs to traverse a single physical link between two switches. Which technology should be implemented?

A) VLAN trunking
B) Port security
C) STP
D) DHCP snooping

Answer: A) VLAN trunking

Explanation:

A) VLAN trunking enables multiple VLANs to share a single physical link between network switches. This technology tags frames with VLAN identifiers using protocols like IEEE 802.1Q, allowing devices on different VLANs to send traffic over the same link without mixing broadcast domains. Trunking is essential in enterprise networks to minimize cabling, optimize bandwidth usage, and support complex segmented networks. It allows for inter-VLAN traffic transport while maintaining isolation between VLANs. Trunk ports can carry tagged traffic from multiple VLANs, while access ports carry traffic for a single VLAN. Proper configuration ensures that devices on separate VLANs remain logically isolated even if the same physical connection is used, supporting security policies and performance optimization. Trunking is widely deployed in core, distribution, and access layers of enterprise networks, where multiple VLANs need to interconnect efficiently.

B) Port security restricts access to a switch port based on MAC addresses. While it prevents unauthorized devices from connecting, it does not allow multiple VLANs to traverse a single physical link. Port security controls access but does not manage VLAN traffic transport.

C) STP prevents Layer 2 loops by selectively blocking redundant paths in the network. While critical for stability, STP does not provide the ability to transport multiple VLANs over a single link. It addresses topology management rather than VLAN traffic segregation or aggregation.

D) DHCP snooping validates DHCP server responses to prevent rogue IP assignments. While enhancing network security, DHCP snooping does not facilitate multiple VLANs over a single link or tag traffic appropriately. Its function is limited to controlling DHCP traffic, not VLAN transport.

VLAN trunking is the only technology that allows multiple VLANs to traverse a single physical link while maintaining traffic segregation, making it the correct choice.

Question 137

A technician wants to monitor which devices are consuming the most bandwidth on a network to troubleshoot performance issues. Which tool is most appropriate?

A) SNMP
B) Netstat
C) ARP
D) Traceroute

Answer: A) SNMP

Explanation:

A) SNMP (Simple Network Management Protocol) is a protocol used to monitor, manage, and configure network devices. It collects performance metrics such as bandwidth utilization, packet errors, interface status, and device health. SNMP can be used with network management systems (NMS) to generate graphs, alerts, and reports, helping administrators identify which devices or interfaces consume the most bandwidth. SNMP supports multiple versions, including SNMPv2 and SNMPv3, with v3 providing authentication and encryption for secure monitoring. It is highly scalable, allowing monitoring of hundreds or thousands of devices in enterprise environments. SNMP polling and traps provide detailed insight into traffic patterns, enabling administrators to troubleshoot congestion, plan capacity, and optimize network performance. By analyzing SNMP data, network engineers can make informed decisions about upgrades, reconfigurations, and policy enforcement.

B) Netstat shows active connections, listening ports, and routing tables on a host. While useful for examining sessions or identifying connections, Netstat does not provide comprehensive metrics about bandwidth utilization across the network or historical traffic patterns.

C) ARP maps IP addresses to MAC addresses on a local network. While ARP tables are important for Layer 2 communication, they do not provide metrics on bandwidth consumption or device performance, making them unsuitable for troubleshooting network congestion.

D) Traceroute identifies the path packets take between devices and measures per-hop latency. While useful for locating routing issues, Traceroute does not provide data on bandwidth consumption or traffic usage by devices, so it cannot help identify the heaviest network consumers.

SNMP provides detailed, scalable network monitoring and bandwidth analysis, making it the correct choice for troubleshooting performance issues.

Question 138

A network engineer wants to prevent rogue DHCP servers from assigning IP addresses on the network. Which feature should be enabled?

A) DHCP snooping
B) Port security
C) STP
D) VLAN trunking

Answer: A) DHCP snooping

Explanation:

A) DHCP snooping is a security feature that prevents unauthorized DHCP servers from issuing IP addresses. It works by designating trusted ports (connected to legitimate DHCP servers) and untrusted ports (connected to clients). DHCP snooping inspects messages such as DHCP Discover and Offer to ensure only trusted servers respond to requests. It also maintains a binding table mapping client MAC addresses, IP addresses, VLANs, and switch ports. By enforcing DHCP server legitimacy, it prevents rogue devices from providing incorrect IP information, default gateways, or DNS settings, which could lead to man-in-the-middle attacks, IP conflicts, or network outages. DHCP snooping can also integrate with IP Source Guard and Dynamic ARP Inspection for a layered security approach, providing enhanced protection for enterprise networks.

B) Port security restricts access to switch ports by limiting the MAC addresses allowed on a port. While it prevents unauthorized devices from connecting, it does not validate DHCP server responses and cannot prevent rogue IP assignment from unauthorized DHCP servers.

C) STP prevents Layer 2 loops by blocking redundant paths. While essential for network stability, it does not monitor or secure DHCP traffic and cannot prevent rogue servers from assigning addresses.

D) VLAN trunking allows multiple VLANs to share a single link. It is used for transporting VLAN traffic but provides no DHCP security. VLAN trunking does not inspect DHCP messages or enforce server trust.

DHCP snooping specifically prevents rogue DHCP servers from distributing IP addresses and ensures network reliability, making it the correct choice.

Question 139

 A network administrator wants to isolate broadcast traffic in a large enterprise network to improve performance and security. Which technology should be implemented?

A) VLANs
B) LACP
C) STP
D) Port security

Answer: A) VLANs

Explanation:

A) VLANs divide a physical network into multiple logical broadcast domains, isolating broadcast traffic from other segments. This reduces unnecessary broadcast storms, improves network performance, and enhances security by limiting communication to only devices within the same VLAN unless routed through a Layer 3 device. VLANs are flexible, allowing administrators to group users by department, function, or security level without additional physical infrastructure. They facilitate traffic management, troubleshooting, and implementation of policies such as access control lists and Quality of Service. By isolating broadcast domains, VLANs ensure that broadcast traffic from one segment does not affect others, improving overall network efficiency. Enterprise networks benefit from VLANs because they reduce congestion, increase scalability, and provide better control over user access and network resources.

B) LACP aggregates multiple physical links to increase bandwidth and provide redundancy. While beneficial for throughput and fault tolerance, LACP does not isolate broadcast traffic or create separate broadcast domains.

C) STP prevents loops by blocking redundant Layer 2 paths. While crucial for network stability, it does not segment the network or reduce broadcast traffic. STP ensures loop-free topology but cannot isolate traffic for performance improvement.

D) Port security restricts access to switch ports based on MAC addresses. It prevents unauthorized devices from connecting but does not reduce broadcast traffic or segment the network. Its focus is security at the port level, not traffic isolation.

VLANs provide broadcast isolation, performance improvement, and security enhancements, making them the correct choice.

Question 140

 A network engineer needs to reduce congestion and interference in a high-density Wi-Fi environment. Which action is most effective?

A) Move clients to the 5 GHz band
B) Increase DHCP lease time
C) Enable Telnet on the access point
D) Reduce MTU size

Answer: A) Move clients to the 5 GHz band

Explanation:

A) Moving clients to the 5 GHz band reduces congestion and interference caused by the crowded 2.4 GHz spectrum. The 2.4 GHz band is heavily utilized by Wi-Fi devices, Bluetooth devices, and other consumer electronics, which can result in co-channel and adjacent-channel interference. The 5 GHz band provides more non-overlapping channels, higher data rates, and less interference, allowing for improved throughput and performance. Although 5 GHz signals have shorter range and higher attenuation, strategic placement of access points ensures adequate coverage. In high-density environments, shifting clients to 5 GHz reduces collisions, improves channel reuse, and enhances user experience for applications such as VoIP, video streaming, and large file transfers. By optimizing frequency allocation and minimizing interference, administrators can maintain a stable, high-performance wireless network even in environments with many devices.

B) Increasing DHCP lease time reduces the frequency of IP address requests but does not impact wireless congestion or RF interference. It only affects IP management, not performance.

C) Enabling Telnet on an access point allows remote management but does not influence wireless interference or client throughput. It is a management protocol and has no effect on RF performance.

D) Reducing MTU size changes the maximum packet size and may reduce fragmentation in some scenarios. However, it does not reduce interference, congestion, or improve throughput in high-density Wi-Fi environments.

Moving clients to the 5 GHz band directly addresses interference and congestion, improving throughput and network performance, making it the correct choice.