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

Question 1: What is the purpose of a WAN edge router?

To provide NAT services for internal servers
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)

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

DHCP (Correct answer)
DNS
HTTP
FTP

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 3: What is NetFlow used for in network management?

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

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

To block unauthorized DHCP servers and validate DHCP messages (Correct answer)
To encrypt DHCP messages
To assign static IPs based on MAC addresses
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 5: What is the primary purpose of a network switch?

To route traffic between different IP networks
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 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 6: Which syslog severity level indicates a condition that requires immediate action to prevent system failure?

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

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

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

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

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

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

Modem
Firewall
Switch (Correct answer)
Router

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

SSH (Secure Shell) (Correct answer)
Telnet
HTTP
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 11: Which Wi-Fi standard introduced support for speeds up to 1 Gbps and operates in the 5 GHz band?

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

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

It increases STP convergence speed on trunk ports
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 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 14: Which type of ACL can filter traffic based on both source and destination IP addresses and port numbers?

Standard ACL
Extended ACL (Correct answer)
Reflexive 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 15: What is the role of the Network Layer in the OSI model?

To provide encryption and security
To control the physical connection between devices
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 16: What does the 'show mac address-table' command display on a Cisco switch?

Configured VLANs and their associated ports
Dynamically learned and static MAC-to-port mappings (Correct answer)
STP topology and port roles
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 17: What does syslog provide in a network management context?

Automatic backup of device configurations
Real-time bandwidth utilization graphs
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 does NFV (Network Functions Virtualization) primarily aim to achieve?

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

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 19: What does the term 'zero-day vulnerability' mean?

A vulnerability only exploitable for 24 hours
A vulnerability in newly deployed network hardware
A vulnerability that is publicly known but has no vendor patch yet (Correct answer)
A vulnerability with a patch available for zero days

Correct answer: A vulnerability that is publicly known but has no vendor patch yet

A zero-day vulnerability is one that is unknown to the vendor, meaning zero days have passed since the vendor became aware — leaving systems unpatched.

Question 20: What does a 'request timed out' response to a ping indicate?

The source interface is down
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

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 21: Which feature prevents traffic from being forwarded from one access port to another on the same VLAN, enhancing security?

Private VLAN (PVLAN) / Protected Ports (Correct answer)
Storm Control
VLAN ACL
Spanning Tree

Correct answer: Private VLAN (PVLAN) / Protected Ports

Private VLANs or protected ports (port isolation) block Layer 2 communication between ports in the same VLAN, forcing traffic through a router/firewall.

Question 22: What is a key advantage of using overlay networks in a network virtualization architecture?

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
They eliminate the need for physical switches entirely

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

Syslog
SNMP (Simple Network Management Protocol) (Correct answer)
NetFlow
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 24: Which frequency bands are commonly used for Wi-Fi networking?

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

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

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

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

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

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

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

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

Single Service Identifier
Security Set Identifier
Secure Service 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 29: Which type of malware disguises itself as legitimate software but performs malicious actions when executed?

Ransomware
Trojan horse (Correct answer)
Worm
Rootkit

Correct answer: Trojan horse

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

Question 30: What is the purpose of a subnet mask in an IP 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
To assign MAC addresses to devices
To hide the IP address of devices on a 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.

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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