CompTIA Network+ (N10-009) — Questions and Answers

Question 1: What does a 'request timed out' response to a ping indicate?

The destination host is reachable but is rejecting ICMP
The destination is unreachable or ICMP responses are being blocked (Correct answer)
There is a DNS resolution failure
The source interface is down

Correct answer: The destination is unreachable or ICMP responses are being blocked

A timeout means no ICMP Echo Reply was received within the timeout period, indicating the destination is unreachable, too slow, or has ICMP blocked by a firewall.

Question 2: Which type of malware disguises itself as legitimate software but performs malicious actions when executed?

Rootkit
Trojan horse (Correct answer)
Worm
Ransomware

Correct answer: Trojan horse

A Trojan horse appears as a benign or useful program but contains hidden malicious code that executes upon installation.

Question 3: What tool is used to identify the path packets take from a source to a destination and detect where delays occur?

netstat
nslookup
ping
traceroute / tracert (Correct answer)

Correct answer: traceroute / tracert

Traceroute (tracert on Windows) sends packets with increasing TTL values to discover each hop in the path and measure round-trip time at each hop.

Question 4: What is a VTEP (VXLAN Tunnel Endpoint)?

A device or software component that encapsulates and decapsulates VXLAN packets (Correct answer)
A monitoring agent used to track tunnel health metrics
A virtual router that connects VXLAN segments to external networks
A protocol for managing VXLAN traffic policies

Correct answer: A device or software component that encapsulates and decapsulates VXLAN packets

A VTEP is responsible for encapsulating Ethernet frames into VXLAN UDP packets and decapsulating them at the destination, serving as the edge of the VXLAN tunnel.

Question 5: Which device operates at the Data Link Layer and is used to connect devices within a Local Area Network (LAN)?

Switch (Correct answer)
Router
Firewall
Modem

Correct answer: Switch

A switch operates at the Data Link Layer (Layer 2) and is used to connect devices within the same network, forwarding data to the correct device based on MAC addresses.

Question 6: What is the primary purpose of a network switch?

To connect devices within the same network and forward data to the correct device (Correct answer)
To assign IP addresses to devices in a network
To route traffic between different IP networks
To connect multiple networks together

Correct answer: To connect devices within the same network and forward data to the correct device

A network switch operates at the data link layer (Layer 2) and is used to connect devices within a LAN, directing data to its intended destination.

Question 7: What does the term "routing table" refer to?

A table that shows the physical layout of a network
A table that lists all IP addresses in a network
A table used by routers to determine the best path for forwarding packets (Correct answer)
A table that records user access to network resources

Correct answer: A table used by routers to determine the best path for forwarding packets

The routing table contains information about network destinations and the best paths to reach them, used by routers to forward packets.

Question 8: What is the difference between SNMPv2c and SNMPv3?

SNMPv3 only supports read-only operations
SNMPv3 uses TCP while SNMPv2c uses UDP
SNMPv2c supports more MIB objects than SNMPv3
SNMPv3 adds authentication and encryption; SNMPv2c uses community strings with no encryption (Correct answer)

Correct answer: SNMPv3 adds authentication and encryption; SNMPv2c uses community strings with no encryption

SNMPv3 introduces USM (User Security Model) with MD5/SHA authentication and DES/AES encryption, replacing the insecure plaintext community strings of SNMPv2c.

Question 9: Which attack floods a target with SYN packets without completing the TCP three-way handshake?

Teardrop attack
Ping flood
SYN flood (Correct answer)
Smurf attack

Correct answer: SYN flood

A SYN flood exhausts server connection tables by leaving half-open TCP sessions, resulting in a denial-of-service condition.

Question 10: What is the role of the Network Layer in the OSI model?

To control the physical connection between devices
To provide encryption and security
To manage the routing of data packets between devices (Correct answer)
To handle error detection and correction

Correct answer: To manage the routing of data packets between devices

The Network Layer (Layer 3) is responsible for determining the best path for data to travel from the source to the destination across different networks.

Question 11: Which Wi-Fi standard introduced support for speeds up to 1 Gbps and operates in the 5 GHz band?

802.11n
802.11b
802.11ac (Correct answer)
802.11a

Correct answer: 802.11ac

The 802.11ac standard, also known as Wi-Fi 5, introduced higher speeds and operates primarily in the 5 GHz band.

Question 12: What does a high number of CRC errors on a switch interface typically indicate?

An overloaded routing table
Physical layer issues such as bad cable, duplex mismatch, or faulty NIC (Correct answer)
An incorrect VLAN assignment
A routing loop in the network

Correct answer: Physical layer issues such as bad cable, duplex mismatch, or faulty NIC

CRC errors indicate corrupted frames, most commonly caused by physical problems: damaged cables, duplex mismatches, or faulty hardware.

Question 13: What does 'interface utilization threshold alerting' in an NMS help network engineers accomplish?

Proactively identify links approaching saturation before performance degrades (Correct answer)
Detect unauthorized devices connected to monitored interfaces
Automatically reroute traffic when links are saturated
Balance traffic loads across all available interfaces

Correct answer: Proactively identify links approaching saturation before performance degrades

Utilization threshold alerts (e.g., alert at 80% utilization) give engineers advance warning to add capacity before users experience performance degradation.

Question 14: What is the primary purpose of a wireless access point (AP)?

To manage network security
To connect multiple wired networks
To provide a wireless connection to a wired network (Correct answer)
To route traffic between different networks

Correct answer: To provide a wireless connection to a wired network

A wireless access point connects wireless devices to a wired network, enabling wireless communication within a network.

Question 15: What does the 'show mac address-table' command display on a Cisco switch?

Dynamically learned and static MAC-to-port mappings (Correct answer)
STP topology and port roles
Configured VLANs and their associated ports
Interface duplex and speed settings

Correct answer: Dynamically learned and static MAC-to-port mappings

The MAC address table maps learned MAC addresses to the switch ports they were learned on, enabling frame forwarding decisions.

Question 16: Which protocol is most commonly used to monitor and manage network devices by querying MIB objects?

NetFlow
SNMP (Simple Network Management Protocol) (Correct answer)
Syslog
TACACS+

Correct answer: SNMP (Simple Network Management Protocol)

SNMP allows network management systems (NMS) to query and configure devices using MIB (Management Information Base) object identifiers.

Question 17: What does syslog provide in a network management context?

Real-time bandwidth utilization graphs
Automatic backup of device configurations
Centralized logging of device events and alerts for auditing and troubleshooting (Correct answer)
Active polling of device performance metrics

Correct answer: Centralized logging of device events and alerts for auditing and troubleshooting

Syslog forwards timestamped event messages from network devices to a centralized server, enabling audit trails and rapid troubleshooting.

Question 18: What is the purpose of a CMDB (Configuration Management Database) in network operations?

To store encrypted credentials for all network devices
To maintain a repository of all network assets, their configurations, relationships, and change history (Correct answer)
To provide automated network provisioning for new devices
To serve as the primary DNS resolver for the network

Correct answer: To maintain a repository of all network assets, their configurations, relationships, and change history

A CMDB tracks all network assets (hardware, software, configurations) and their interdependencies, supporting change management, incident response, and compliance auditing.

Question 19: A duplex mismatch between a switch port and a connected device will cause which symptom?

High number of late collisions and poor throughput (Correct answer)
Complete loss of connectivity
Increased broadcast traffic
VLAN membership errors

Correct answer: High number of late collisions and poor throughput

A duplex mismatch (one side full-duplex, other half-duplex) causes late collisions on the half-duplex side and reduced throughput without complete link failure.

Question 20: In STP, what is the role of the Root Bridge?

It provides DHCP services
It forwards traffic between VLANs
It manages trunk negotiation
It serves as the reference point for all STP path calculations in the network (Correct answer)

Correct answer: It serves as the reference point for all STP path calculations in the network

The Root Bridge is the STP reference point; all switches calculate their best path (lowest cost) toward the root bridge to build a loop-free topology.

Question 21: Which type of ACL can filter traffic based on both source and destination IP addresses and port numbers?

Reflexive ACL
Extended ACL (Correct answer)
Standard ACL
Dynamic ACL

Correct answer: Extended ACL

Extended ACLs (Cisco numbered 100–199) match on source/destination IP, protocol, and port, giving granular traffic control.

Question 22: In the context of WAN SLAs, what does jitter measure?

Variation in packet delay over time (Correct answer)
Average round-trip delay across the WAN link
Maximum throughput of the WAN circuit
Percentage of packets lost in transit

Correct answer: Variation in packet delay over time

Jitter is the variation in packet inter-arrival times; high jitter degrades real-time applications like VoIP because packets arrive at inconsistent intervals.

Question 23: Which security framework is commonly used for US federal agencies and their contractors to manage cybersecurity risk?

NIST Cybersecurity Framework (CSF) (Correct answer)
SOC 2
PCI DSS
ISO 27001

Correct answer: NIST Cybersecurity Framework (CSF)

The NIST CSF provides guidelines for identifying, protecting, detecting, responding to, and recovering from cybersecurity events.

Question 24: What is a key advantage of using overlay networks in a network virtualization architecture?

They eliminate the need for physical switches entirely
They automatically assign VLANs to end devices
They provide logical network isolation independent of the physical topology (Correct answer)
They automatically reduce IP address consumption

Correct answer: They provide logical network isolation independent of the physical topology

Overlay networks create logical topologies on top of the physical underlay, providing isolation and flexibility without requiring changes to the underlying physical infrastructure.

Question 25: What is the IANA-assigned standard UDP destination port used by VXLAN?

4500
4789 (Correct answer)
6635
8472

Correct answer: 4789

IANA assigned UDP port 4789 as the standard VXLAN destination port, though some early implementations used 8472.

Question 26: What is the default port cost for a 1 Gbps link in IEEE 802.1D Spanning Tree Protocol?

1000
4
19 (Correct answer)
100

Correct answer: 19

IEEE 802.1D assigns a cost of 19 to 1 Gbps links, used by STP to determine the best path to the root bridge.

Question 27: What is the most effective first step when troubleshooting a reported network outage?

Immediately reboot the affected routers and switches
Clear all routing tables and re-establish adjacencies
Define and document the problem by gathering information from affected users and systems (Correct answer)
Replace the suspected faulty cable

Correct answer: Define and document the problem by gathering information from affected users and systems

Effective troubleshooting begins with defining the problem — understanding scope, symptoms, and recent changes before making any modifications.

Question 28: What is a CIR (Committed Information Rate) in Frame Relay or MPLS services?

The latency SLA for the WAN connection
The guaranteed minimum bandwidth the service provider commits to deliver (Correct answer)
The maximum burst speed allowed on the circuit
The cost per gigabyte of transferred data

Correct answer: The guaranteed minimum bandwidth the service provider commits to deliver

CIR is the contracted minimum bandwidth that the service provider guarantees to deliver under normal conditions; traffic above the CIR may be discarded during congestion.

Question 29: What is the function of PortFast in Cisco STP implementations?

It enables BPDU filtering on all ports
It allows access ports connected to end devices to skip STP listening and learning states (Correct answer)
It increases STP convergence speed on trunk ports
It elects the root bridge faster

Correct answer: It allows access ports connected to end devices to skip STP listening and learning states

PortFast immediately transitions an access port to the Forwarding state, avoiding the typical 30-second STP delay for end device connections.

Question 30: In a leaf-spine data center fabric architecture, what is the primary role of leaf switches?

Running the SDN controller software for the fabric
Providing WAN connectivity to external networks and the internet
Connecting servers and end devices to the network fabric (Correct answer)
Interconnecting spine switches to provide path redundancy

Correct answer: Connecting servers and end devices to the network fabric

Leaf switches serve as the access layer in a leaf-spine architecture, connecting servers, storage, and other endpoints to the spine layer for any-to-any connectivity.

Question 31: What is microsegmentation in the context of network virtualization?

Applying granular security policies to individual workloads or virtual machines (Correct answer)
Segmenting traffic flows by packet size or protocol
Creating VLANs with fewer than 10 devices each
Dividing a network into multiple physical cable segments

Correct answer: Applying granular security policies to individual workloads or virtual machines

Microsegmentation applies fine-grained security policies at the workload or VM level, enabling east-west traffic control within a data center to limit lateral movement.

Question 32: Which VPN protocol uses UDP port 500 and ESP to create encrypted tunnels between sites?

PPTP
L2TP/IPsec
SSL/TLS VPN
IPsec IKEv2 (Correct answer)

Correct answer: IPsec IKEv2

IPsec IKEv2 uses UDP 500 for key exchange and ESP (Encapsulating Security Payload) for encryption and integrity.

Question 33: Which firewall type inspects traffic at the application layer and can filter based on application-specific data?

Packet filter firewall
Circuit-level gateway
Stateful inspection firewall
Next-generation firewall (NGFW) (Correct answer)

Correct answer: Next-generation firewall (NGFW)

NGFWs operate at Layer 7 and can identify applications regardless of port number, enabling deep packet inspection.

Question 34: Which WAN technology uses asymmetric speeds and is delivered over existing telephone copper lines?

Cable (DOCSIS)
DSL (xDSL) (Correct answer)
Fiber optic (GPON)
T1 leased line

Correct answer: DSL (xDSL)

DSL delivers broadband over telephone copper pairs with faster download speeds than upload, with variants including ADSL, VDSL, and G.fast.

Question 35: What is the primary purpose of a demilitarized zone (DMZ) in network security?

To segment wireless networks from wired networks
To provide VPN termination points
To host public-facing servers while protecting the internal network (Correct answer)
To isolate internal users from each other

Correct answer: To host public-facing servers while protecting the internal network

A DMZ places public-facing servers (web, mail, DNS) in a separate zone so that even if compromised, attackers cannot directly access the internal LAN.

Question 36: Which WAN circuit type provides a dedicated point-to-point connection with guaranteed bandwidth between two locations?

Satellite internet
DSL
Leased line (T1/E1) (Correct answer)
Cable broadband

Correct answer: Leased line (T1/E1)

Leased lines like T1 (1.544 Mbps) or E1 (2.048 Mbps) are dedicated circuits providing constant guaranteed bandwidth and low latency for enterprise WAN links.

Question 37: Which type of hypervisor runs directly on physical hardware without requiring a host operating system?

Container runtime hypervisor
Type 1 hypervisor (Correct answer)
Type 2 hypervisor
Hosted hypervisor

Correct answer: Type 1 hypervisor

Type 1 (bare-metal) hypervisors run directly on hardware without a host OS; examples include VMware ESXi and Microsoft Hyper-V.

Question 38: Which command verifies end-to-end IP reachability between two hosts?

netstat
traceroute
ipconfig
ping (Correct answer)

Correct answer: ping

Ping sends ICMP Echo Request packets to a destination and reports whether responses are received, confirming IP-layer reachability.

Question 39: What is the maximum number of unique VLAN IDs supported by the IEEE 802.1Q standard?

16,777,214
1024
4094 (Correct answer)
256

Correct answer: 4094

IEEE 802.1Q uses a 12-bit VLAN ID field, supporting VLANs 1–4094 (4,096 total values, with 0 and 4095 reserved).

Question 40: Which syslog severity level indicates a condition that requires immediate action to prevent system failure?

Level 1 - Alert (Correct answer)
Level 4 - Warning
Level 0 - Emergency
Level 2 - Critical

Correct answer: Level 1 - Alert

Syslog Level 1 (Alert) means 'immediate action needed' — higher than Critical (2) but below Emergency (0) which indicates the system is unusable.

Question 41: What does the acronym "LAN" stand for?

Long Area Network
Large Area Network
Local Area Network (Correct answer)
Logical Access Network

Correct answer: Local Area Network

A Local Area Network (LAN) is a network that connects devices within a limited geographic area, such as a home, office, or building.

Question 42: What protocol is used to negotiate EtherChannel formation in a standards-based (non-proprietary) environment?

LACP (802.3ad) (Correct answer)
CDP
LLDP
PAgP

Correct answer: LACP (802.3ad)

LACP (Link Aggregation Control Protocol) is the IEEE standard for negotiating EtherChannel, while PAgP is Cisco proprietary.

Question 43: Which tool captures and analyzes network packets at the wire level for deep inspection during troubleshooting?

SNMP manager
Syslog server
Protocol analyzer (e.g., Wireshark) (Correct answer)
NetFlow collector

Correct answer: Protocol analyzer (e.g., Wireshark)

Protocol analyzers like Wireshark capture raw frames from the network, decoding protocols layer by layer for detailed inspection of traffic and identification of anomalies.

Question 44: What is the function of LLDP (Link Layer Discovery Protocol)?

To allow network devices to advertise identity and capability information to directly connected neighbors (Correct answer)
To dynamically assign VLANs based on device type
To negotiate trunk and access port modes between switches
To detect and prevent Layer 2 switching loops

Correct answer: To allow network devices to advertise identity and capability information to directly connected neighbors

LLDP (IEEE 802.1AB) is a vendor-neutral protocol that lets devices announce their identity, capabilities, and connected port info to adjacent devices for topology discovery.

Question 45: What is an inter-VLAN routing method that uses a single trunk link between a router and a switch?

Proxy ARP routing
Router-on-a-stick (Correct answer)
Static routing
Layer 3 switching

Correct answer: Router-on-a-stick

Router-on-a-stick uses subinterfaces on the router, each associated with a VLAN, to route traffic between VLANs over one physical trunk link.

Question 46: In an SDN architecture, what is the 'northbound API' used for?

Communication between SDN applications and the SDN controller (Correct answer)
Connecting physical switches to virtual network overlays
Communication between the SDN controller and network forwarding devices
Routing traffic from southern to northern data center regions

Correct answer: Communication between SDN applications and the SDN controller

The northbound API enables SDN applications and business logic to communicate with and program the SDN controller, abstracting the underlying network capabilities.

Question 47: Which protocol provides secure, encrypted access to the CLI of network devices for management purposes?

HTTP
SSH (Secure Shell) (Correct answer)
Telnet
SNMP

Correct answer: SSH (Secure Shell)

SSH encrypts the management session between the engineer's terminal and the network device, preventing credential and command interception unlike Telnet.

Question 48: What is the advantage of using a network configuration management tool (e.g., Ansible, RANCID)?

It monitors device CPU and memory in real time
It automates configuration backup, version control, and change tracking across all network devices (Correct answer)
It generates network topology diagrams automatically
It automatically optimizes routing tables

Correct answer: It automates configuration backup, version control, and change tracking across all network devices

Configuration management tools automate config backup, track changes over time, enforce compliance, and enable rapid rollback after a misconfiguration.

Question 49: Which encryption protocol replaced WEP and is considered insecure due to its use of RC4?

WPA3
TKIP (WPA) (Correct answer)
AES-CCMP
WPA2

Correct answer: TKIP (WPA)

WPA with TKIP was designed as a temporary fix for WEP but still uses RC4 and has known vulnerabilities like the TKIP MIC exploit.

Question 50: Which metric does MPLS Traffic Engineering (TE) use to calculate constrained paths across the network?

STP port cost
Bandwidth, delay, and administrative constraints via RSVP-TE or OSPF-TE extensions (Correct answer)
BGP MED values
Hop count

Correct answer: Bandwidth, delay, and administrative constraints via RSVP-TE or OSPF-TE extensions

MPLS-TE uses extensions to OSPF or IS-IS to flood topology and bandwidth information, then RSVP-TE signals explicit LSPs that satisfy bandwidth and policy constraints.

Question 51: Which switching method begins forwarding a frame before it is fully received, reducing latency?

Store-and-forward
Fragment-free
Cut-through (Correct answer)
Adaptive cut-through

Correct answer: Cut-through

Cut-through switching begins forwarding after reading only the destination MAC address, at the cost of possibly forwarding corrupt frames.

Question 52: What is the primary purpose of VXLAN (Virtual Extensible LAN)?

To extend Layer 2 networks over a Layer 3 infrastructure (Correct answer)
To provide encryption for wireless networks
To replace VLANs entirely in small networks
To manage IP address allocation across data centers

Correct answer: To extend Layer 2 networks over a Layer 3 infrastructure

VXLAN encapsulates Layer 2 Ethernet frames in UDP packets, allowing Layer 2 network segments to span a Layer 3 routed infrastructure.

Question 53: What does the term "SSID" stand for in wireless networking?

Secure Service Identifier
Single Service Identifier
Security Set Identifier
Service Set Identifier (Correct answer)

Correct answer: Service Set Identifier

SSID (Service Set Identifier) is the name of a wireless network that devices use to identify and connect to it.

Question 54: Which device is used to connect different networks and direct data between them?

Modem
Router (Correct answer)
Switch
Hub

Correct answer: Router

A router operates at the network layer (Layer 3) and is responsible for routing data between different IP networks.

Question 55: What does an 'administratively down' interface status indicate on a Cisco device?

The interface has been manually shut down with the 'shutdown' command (Correct answer)
The interface has lost its physical signal
The STP port is in a blocking state
The interface has failed due to a hardware error

Correct answer: The interface has been manually shut down with the 'shutdown' command

Administratively down means an operator used the 'shutdown' command to disable the interface; the 'no shutdown' command restores it to an active state.

Question 56: What is the primary advantage of the 5 GHz band over the 2.4 GHz band?

Better penetration through walls
Longer range
Lower cost of equipment
Lower susceptibility to interference from other devices (Correct answer)

Correct answer: Lower susceptibility to interference from other devices

The 5 GHz band is less crowded and less prone to interference from devices like microwave ovens and cordless phones compared to the 2.4 GHz band.

Question 57: Which protocol is used to provide centralized device authentication and authorization using a TCP-based connection with encrypted payloads?

Kerberos
LDAP
RADIUS
TACACS+ (Correct answer)

Correct answer: TACACS+

TACACS+ uses TCP port 49 and encrypts the entire payload, providing separate AAA functions; it's preferred over RADIUS for device administration.

Question 58: What is the primary function of a router in a network?

To route data packets between different networks (Correct answer)
To assign IP addresses to devices
To provide a wireless connection to devices
To connect devices within the same local area network

Correct answer: To route data packets between different networks

Routers direct data packets from one network to another, determining the best path for the data to travel based on IP addresses.

Question 59: Which protocol is most commonly used as the southbound API in SDN for communication between an SDN controller and network forwarding devices?

SNMP
BGP
OpenFlow (Correct answer)
OSPF

Correct answer: OpenFlow

OpenFlow is the primary southbound API protocol that allows SDN controllers to program the forwarding tables of network devices.

Question 60: What does NFV (Network Functions Virtualization) primarily aim to achieve?

Replace physical switches with software-only virtual switches
Virtualize IP address management across clouds
Create encrypted tunnels between data center locations
Run network functions as software on commodity hardware (Correct answer)

Correct answer: Run network functions as software on commodity hardware

NFV enables network functions such as firewalls, load balancers, and routers to run as software (VNFs) on standard commodity servers instead of dedicated proprietary appliances.

Question 61: What does the 802.1X standard provide in a network environment?

Port-based Network Access Control (NAC) (Correct answer)
VLAN tagging
Link aggregation
Spanning Tree Protocol

Correct answer: Port-based Network Access Control (NAC)

802.1X enforces authentication before allowing a device to access the network, requiring credentials verified by a RADIUS server.

Question 62: What does SDN (Software-Defined Networking) fundamentally separate within a network architecture?

Management plane from the control plane
Data plane from the physical hardware
Control plane from the data plane (Correct answer)
Application plane from the management plane

Correct answer: Control plane from the data plane

SDN separates the control plane (decision-making logic) from the data plane (packet forwarding), enabling centralized, programmable network management.

Question 63: What does RSPAN (Remote SPAN) allow compared to standard SPAN port mirroring?

RSPAN encrypts mirrored traffic before forwarding it
RSPAN mirrors traffic in both directions simultaneously
RSPAN allows mirroring traffic to a port on a different switch across the network (Correct answer)
RSPAN filters mirrored traffic by VLAN

Correct answer: RSPAN allows mirroring traffic to a port on a different switch across the network

RSPAN extends port mirroring across multiple switches using a dedicated VLAN, allowing a network analyzer connected to a remote switch to capture traffic from source ports.

Question 64: Which protocol is used to automatically assign IP addresses to devices on a network?

DHCP (Correct answer)
HTTP
FTP
DNS

Correct answer: DHCP

Dynamic Host Configuration Protocol (DHCP) is used to automatically assign IP addresses and other network configuration parameters to devices on a network.

Question 65: What is a site-to-site VPN primarily used for in WAN connectivity?

Connecting two geographically separate networks over a public internet connection with encryption (Correct answer)
Replacing MPLS with BGP routing
Accelerating application delivery across WAN links
Providing remote employees access to corporate resources

Correct answer: Connecting two geographically separate networks over a public internet connection with encryption

Site-to-site VPNs create encrypted tunnels between gateway devices at two sites, allowing branch and headquarters to communicate securely over the internet.

Question 66: What is the purpose of NTP (Network Time Protocol) in a managed network?

To schedule configuration backups across devices
To synchronize routing tables between routers
To synchronize clocks across all network devices for consistent log timestamps and security operations (Correct answer)
To provide DHCP failover between servers

Correct answer: To synchronize clocks across all network devices for consistent log timestamps and security operations

NTP synchronizes device clocks to a reference time source, ensuring accurate log timestamps, certificate validity checks, and security event correlation.

Question 67: What does RSTP (802.1w) provide compared to traditional STP (802.1D)?

Faster convergence by introducing new port roles and states (Correct answer)
Per-VLAN spanning tree instances
VLAN pruning across trunk links
Load balancing across redundant links

Correct answer: Faster convergence by introducing new port roles and states

RSTP reduces convergence time from 30–50 seconds to near-zero by introducing Alternate and Backup port roles and eliminating the Listening state.

Question 68: What is the purpose of a network management VLAN (or out-of-band management network)?

To separate management traffic from user data traffic, reducing the attack surface (Correct answer)
To assign static IPs to all network devices automatically
To enable routing between management systems and user devices
To provide higher bandwidth for management traffic

Correct answer: To separate management traffic from user data traffic, reducing the attack surface

An out-of-band management network or dedicated management VLAN isolates device administration from production traffic, reducing security risk and ensuring management access during outages.

Question 69: Which frequency bands are commonly used for Wi-Fi networking?

1.8 GHz and 3.6 GHz
6 GHz and 10 GHz
900 MHz and 1.2 GHz
2.4 GHz and 5 GHz (Correct answer)

Correct answer: 2.4 GHz and 5 GHz

Wi-Fi networks typically operate in the 2.4 GHz and 5 GHz frequency bands, with the 6 GHz band also being used in newer Wi-Fi standards.

Question 70: What is SNMP trapping used for?

Preventing unauthorized SNMP access
Polling device MIBs on a schedule
Encrypting SNMP management traffic
Allowing devices to proactively send unsolicited alerts to the NMS when specific events occur (Correct answer)

Correct answer: Allowing devices to proactively send unsolicited alerts to the NMS when specific events occur

SNMP traps enable devices to immediately notify the NMS of critical events (link down, threshold crossed) without waiting for the next polling cycle.

Question 71: What is the purpose of a subnet mask in an IP network?

To assign MAC addresses to devices
To hide the IP address of devices on a network
To distinguish between the network and host portions of an IP address (Correct answer)
To encrypt data before it is sent over the network

Correct answer: To distinguish between the network and host portions of an IP address

A subnet mask is used to divide an IP address into a network and host portion, determining which part of the address refers to the network and which part refers to the specific device.

Question 72: What is NetFlow used for in network management?

Configuring QoS policies across the network
Encrypting management traffic between the NMS and devices
Collecting and analyzing IP flow data to understand traffic patterns and bandwidth usage (Correct answer)
Synchronizing device configurations

Correct answer: Collecting and analyzing IP flow data to understand traffic patterns and bandwidth usage

NetFlow exports metadata about IP flows (source/dest IP, ports, protocol, byte counts) from routers to a collector, enabling traffic analysis and capacity planning.

Question 73: What is the primary purpose of network flow analysis tools like SolarWinds NTA or ntopng?

To monitor CPU and memory on network devices
To capture and replay network packets for analysis
To configure QoS policies across the network
To identify top talkers, unusual traffic patterns, and bandwidth hogs using flow data (Correct answer)

Correct answer: To identify top talkers, unusual traffic patterns, and bandwidth hogs using flow data

Flow analysis tools process NetFlow/sFlow/IPFIX data to visualize top applications, users, and destinations, enabling bandwidth optimization and anomaly detection.

Question 74: What is the purpose of using 'debug ip routing' on a Cisco router during troubleshooting?

To verify BGP neighbor adjacencies
To show real-time events as routes are added or removed from the routing table (Correct answer)
To display a summary of the routing table
To trace the path of a specific packet

Correct answer: To show real-time events as routes are added or removed from the routing table

'Debug ip routing' logs routing table changes in real time, helping identify route flaps, redistribution issues, or convergence problems — use with caution on production routers.

Question 75: Which SNMP operation allows the NMS to modify a configuration value on a managed device?

GET
SET (Correct answer)
TRAP
GETNEXT

Correct answer: SET

The SNMP SET operation allows the NMS to write a new value to a writable MIB object on the managed device, enabling remote configuration changes.

Question 76: Which layer of the OSI model is responsible for end-to-end communication and error checking?

Data Link Layer
Network Layer
Application Layer
Transport Layer (Correct answer)

Correct answer: Transport Layer

The Transport Layer (Layer 4) ensures reliable data transfer between end systems by handling error checking, data flow control, and re-transmission of lost packets.

Question 77: Which attack involves sending crafted DHCP responses to clients in an attempt to become their default gateway?

DHCP spoofing (Correct answer)
DNS hijacking
DHCP starvation
ARP poisoning

Correct answer: DHCP spoofing

DHCP spoofing involves a rogue DHCP server providing false gateway/DNS info to clients, enabling traffic interception.

Question 78: What is the VNI (VXLAN Network Identifier) used for in a VXLAN deployment?

Encrypting the VXLAN payload data between VTEPs
Setting the QoS priority level for VXLAN encapsulated traffic
Identifying the source IP address of a VXLAN tunnel endpoint
Uniquely identifying a VXLAN segment, similar in concept to a VLAN ID (Correct answer)

Correct answer: Uniquely identifying a VXLAN segment, similar in concept to a VLAN ID

The VNI is a 24-bit identifier in the VXLAN header that uniquely identifies the virtual network segment, supporting up to approximately 16 million unique segments.

Question 79: What is the purpose of a WAN edge router?

To connect wireless access points to the LAN
To aggregate switch ports in the data center
To connect the enterprise LAN to the service provider WAN and manage routing policies (Correct answer)
To provide NAT services for internal servers

Correct answer: To connect the enterprise LAN to the service provider WAN and manage routing policies

The WAN edge router sits at the boundary between the enterprise network and the service provider, handling routing protocols like BGP and policy enforcement.

Question 80: What is the native VLAN in 802.1Q trunking?

The VLAN assigned to all unused ports
The VLAN that carries management traffic only
The VLAN whose frames are sent untagged across the trunk (Correct answer)
The highest-priority VLAN on the trunk

Correct answer: The VLAN whose frames are sent untagged across the trunk

The native VLAN (default VLAN 1) sends and receives untagged frames on 802.1Q trunks; mismatched native VLANs can cause security issues.

Question 81: In VXLAN, how is BUM (Broadcast, Unknown unicast, Multicast) traffic typically handled?

It is replicated to all VTEPs via multicast groups or ingress replication (Correct answer)
It is converted to unicast traffic using ARP suppression only
It is forwarded only to the spine layer switches for processing
It is dropped silently to prevent flooding in the overlay

Correct answer: It is replicated to all VTEPs via multicast groups or ingress replication

BUM traffic in VXLAN is handled using either IP multicast (mapping VNIs to multicast groups) or ingress replication (head-end replication), where the sending VTEP sends a copy to each known remote VTEP.

Question 82: Which metric is most important for measuring WAN link health for real-time voice/video applications?

Packet loss, jitter, and latency (Correct answer)
BGP route count
Total throughput
Number of concurrent connections

Correct answer: Packet loss, jitter, and latency

VoIP and video require low latency (<150ms), low jitter (<30ms), and minimal packet loss (<1%) — these three metrics define quality of real-time communication.

Question 83: What is the main purpose of a network?

To ensure the security of data on a computer
To connect devices to the internet
To monitor the performance of computers
To facilitate the sharing of resources and information (Correct answer)

Correct answer: To facilitate the sharing of resources and information

A network allows multiple devices to communicate and share resources such as files, printers, and internet connections.

Question 84: What is the purpose of DHCP snooping on a switch?

To encrypt DHCP messages
To assign static IPs based on MAC addresses
To block unauthorized DHCP servers and validate DHCP messages (Correct answer)
To forward DHCP requests across VLANs

Correct answer: To block unauthorized DHCP servers and validate DHCP messages

DHCP snooping designates trusted ports (uplinks) and untrusted ports (access), dropping DHCP server replies from untrusted ports.

Question 85: Which protocol is used to centralize authentication, authorization, and accounting for network access?

RADIUS (Correct answer)
LDAP
DHCP
SNMP

Correct answer: RADIUS

RADIUS (Remote Authentication Dial-In User Service) centralizes AAA services, commonly used with 802.1X and VPN authentication.

Question 86: What does the term "IP address" stand for?

Interconnected Protocol address
Internet Protocol address (Correct answer)
Intranet Protocol address
Internal Protocol address

Correct answer: Internet Protocol address

An IP address is a unique address that identifies a device on the internet or a local network.

Question 87: What is the purpose of QoS (Quality of Service) in WAN environments?

To authenticate users connecting to the WAN
To prioritize critical traffic like voice and video over less time-sensitive data (Correct answer)
To encrypt traffic across WAN links
To compress packets for faster transmission

Correct answer: To prioritize critical traffic like voice and video over less time-sensitive data

QoS classifies and prioritizes network traffic, ensuring latency-sensitive applications like VoIP and video conferencing receive guaranteed bandwidth and low delay.

Question 88: Which feature prevents a PortFast-enabled port from causing a topology change if a switch is mistakenly connected to it?

Root Guard
BPDU Guard (Correct answer)
UplinkFast
Loop Guard

Correct answer: BPDU Guard

BPDU Guard places a PortFast-enabled port into err-disabled state if any BPDU is received, preventing rogue switches from affecting the STP topology.

Question 89: What is the purpose of VLAN trunking using 802.1Q?

To assign IP addresses to VLAN interfaces
To carry traffic from multiple VLANs over a single physical link by tagging frames (Correct answer)
To aggregate multiple physical links into one logical link
To prevent loops in a switched network

Correct answer: To carry traffic from multiple VLANs over a single physical link by tagging frames

802.1Q inserts a 4-byte tag into Ethernet frames to identify VLAN membership, allowing multiple VLANs to traverse one trunk link.

Question 90: A network engineer sees 'interface is up, line protocol is down' on a serial interface. What does this indicate?

The IP address is incorrect
Physical connectivity exists but the data link layer is not functioning (e.g., encapsulation mismatch) (Correct answer)
Both physical and logical connectivity are confirmed
The interface has been administratively shut down

Correct answer: Physical connectivity exists but the data link layer is not functioning (e.g., encapsulation mismatch)

Up/down means the physical signal is present (cable connected) but keepalives or LCP negotiation are failing — typically an encapsulation mismatch or clocking issue.

Question 91: What is a Man-in-the-Middle (MitM) attack?

Flooding a network with broadcast traffic
Cracking passwords through dictionary attacks
Exploiting buffer overflow vulnerabilities
Intercepting and potentially altering communication between two parties (Correct answer)

Correct answer: Intercepting and potentially altering communication between two parties

In a MitM attack, the attacker secretly relays and can modify messages between two parties who believe they are communicating directly.

CompTIA Network+ (N10-009)

CompTIA Network+ validates the skills needed to design, configure, manage, and troubleshoot wired and wireless networks. It is the industry benchmark for entry-to-mid-level network engineer roles.

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90 min

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80%

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