N10-009 CompTIA Network+ Certification Exam Free Practice Exam Questions (2026 Updated)

Once the theory has been tested and confirmed, the next step is to implement the solution based on the CompTIA troubleshooting model.

CompTIA Troubleshooting Model:

Identify the problem.

Establish a theory of probable cause.

Test the theory.

Establish a plan of action and implement the solution. ✅ (Correct step)

Verify full system functionality.

Document findings, actions, and outcomes.

Breakdown of Options:

A. Develop a theory – The theory has already been developed and tested.

B. Establish a plan of action – This happens before implementation, but since the issue is confirmed, it ' s time to act.

C. Implement the solution – Correct answer. The problem is confirmed, so the fix should be applied.

D. Document the findings – Documentation is the final step, not the next one.

A jump box is a hardened, isolated system that provides secure access to critical infrastructure devices like routers and firewalls.

Understanding Subnetting:

The subnet mask 255.255.255.240 (or /28) indicates that each subnet has 16 IP addresses (14 usable addresses, 1 network address, and 1 broadcast address).

Calculating the Subnet Range:

Subnet Calculation: For the IP address 10.0.0.95 with a /28 subnet mask:

Network address: 10.0.0.80

Usable IP range: 10.0.0.81 to 10.0.0.94

Broadcast address: 10.0.0.95

Router Interface Configuration:

Broadcast Address Issue: The IP address 10.0.0.95 is the broadcast address for the subnet 10.0.0.80/28. Configuring a router interface with the broadcast address will cause routing issues as it is not a valid host address.

Comparison with Other Options:

The web server is in a different subnet: The web server (10.0.0.81) is within the same subnet range (10.0.0.80/28).

The IP address space is a class A network: While 10.0.0.0 is a Class A network, this does not explain the routing issue caused by the broadcast address.

The subnet is in a private address space: The private address space designation (RFC 1918) does not impact the routing issue related to the broadcast address configuration.

Resolution:

Reconfigure the router interface with a valid host IP address within the usable range, such as 10.0.0.94.

The netstat output shows that multiple ports are open, including Telnet (23), FTP (20), and TFTP (69), which are potential security risks. Disabling unused ports minimizes the attack surface, reducing security vulnerabilities.

Breakdown of Options:

A. Disable the unused ports – Correct answer. Unused ports should be closed to prevent unauthorized access.

B. Enforce access control lists – ACLs help control access but do not disable unnecessary services.

C. Perform content filtering – Content filtering controls web traffic, not port security.

D. Set up a screened subnet – A DMZ (screened subnet) improves security but does not address open ports.

An IP Helper (IP Helper Address) allows DHCP requests to pass through routers and reach a DHCP server on another network.

DHCP broadcasts are not forwarded across routers by default, so an IP Helper Address is needed to relay the request.

This is crucial for large networks where a single DHCP server serves multiple subnets.

Option B (Reservation): Ensures a specific IP address is assigned to a MAC address but does not relay DHCP across networks.

Option C (Exclusion): Prevents specific IP addresses from being assigned, but does not help with DHCP relay.

Option D (Scope): Defines the range of IP addresses available for DHCP clients but does not assist in cross-network communication.

? Reference: CompTIA Network+ (N10-009) Official Study Guide – Section: DHCP and IP Addressing

The correct answer is B. MAC filtering. MAC filtering is a straightforward method of restricting network access by allowing only specific device MAC (Media Access Control) addresses to connect to a wireless network. In a small, stable environment with fewer than ten devices and no expected changes, this approach is simple to implement and manage.

Each network interface card (NIC) has a unique MAC address, and wireless access points can be configured with a whitelist of approved addresses. Devices not on the list are denied access, effectively limiting connectivity to only authorized laptops. This aligns with CompTIA Network+ guidance for basic access control mechanisms in small or low-complexity networks.

Other options are less suitable in this scenario. ACLs (Access Control Lists) are typically used on routers and switches to control traffic flow based on IP addresses or protocols, not specifically device access to a wireless network. NAC (Network Access Control) provides more advanced authentication and posture assessment but is more complex and unnecessary for a small, static environment. Trusted zones refer to network segmentation concepts rather than device-level access control.

Thus, MAC filtering provides the simplest and most appropriate solution.

A jump box is a hardened system that provides secure access to isolated or sensitive devices on a separate network.

Breakdown of Options:

A. Jump box – ✅ Correct answer. Acts as a middle point for secure remote access.

B. API gateway – Used for managing API calls, not remote access to isolated devices.

C. Secure Shell (SSH) – Requires direct connectivity, which may not be available for an isolated device.

D. Clientless VPN – Allows web-based VPN access, but does not guarantee access to isolated devices.

SNMPv3 is the version of the Simple Network Management Protocol that introduces security enhancements, including message integrity, authentication, and encryption. Unlike previous versions (v1 and v2c), SNMPv3 supports encrypted communication, ensuring that data is not transmitted in plaintext. This provides confidentiality and protects against eavesdropping and unauthorized access.References: CompTIA Network+ study materials.

The giveaway here is the 169.254.x.x address. That is an APIPA address, which Windows assigns to itself when it asks for an IP address from DHCP and does not get one. Since there is also no default gateway and no DHCP server listed, the laptop clearly failed to obtain normal network settings.

Out of the choices, address pool exhaustion makes the most sense. If the DHCP scope has run out of available addresses, the client cannot lease one, so it falls back to an automatic private address. At that point, the device may still think its network adapter is working, but it will not be able to reach internal resources like the company intranet because it does not have valid Layer 3 settings for that network.

The other answers do not fit the output. A short lease duration could cause frequent renewals, but it would not normally explain an APIPA address by itself. An IIS problem would affect the web server, not the client’s local IP configuration. An IDS issue also would not cause the workstation to self-assign 169.254.0.5. This is a DHCP addressing problem, and the best answer is C .

A proxy server can filter internet access by controlling which websites or services users can reach. It enforces content policies and can provide caching and monitoring.

A. A router directs traffic but doesn’t filter internet sites by itself.

B. A cloud gateway could also filter, but the most direct answer is proxy.

D. An IDS detects suspicious activity but doesn’t filter browsing access.

References (CompTIA Network+ N10-009):

Domain: Network Security — Proxy servers, filtering, access control.

A cable tester is a tool that can help identify issues with the physical cabling, such as breaks or improper terminations, which may prevent the access point from reaching the internet.

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A CNAME (Canonical Name) record maps an alias to the correct fully qualified domain name (FQDN). If a user is redirected to the wrong hostname, correcting or updating the CNAME ensures the alias points to the proper domain.

B. PTR record maps IP to hostname (reverse DNS), not forward website resolution.

C. NTP relates to time sync, irrelevant to DNS resolution.

D. TXT record stores metadata like SPF or DKIM info, not used for hostname aliasing.

References (CompTIA Network+ N10-009):

Domain: Network Standards, Protocols, and Implementations — DNS record types (A, AAAA, CNAME, PTR, TXT).

Understanding VoIP and VLANs:

VoIP (Voice over IP) phones often use VLANs (Virtual Local Area Networks) to separate voice traffic from data traffic for improved performance and security.

Tagging Traffic to Voice VLAN:

Voice VLAN Configuration: The port on the switch needs to be configured to tag traffic for the specific voice VLAN. This ensures that voice packets are prioritized and handled correctly.

VLAN Tagging: VLAN tagging allows the switch to identify and separate voice traffic from other types of traffic on the network, reducing latency and jitter for VoIP communications.

Comparison with Other Options:

Trunk all VLANs on the port: Trunking all VLANs is typically used for links between switches, not for individual device ports.

Configure the native VLAN: The native VLAN is for untagged traffic and does not address the need for separating and prioritizing voice traffic.

Disable VLANs: Disabling VLANs would mix voice and data traffic, leading to potential performance issues and lack of traffic separation.

Implementation:

Configure the switch port connected to the VoIP phone to tag the traffic for the designated voice VLAN, ensuring proper network segmentation and quality of service.

For a secure 802.1X design that includes BYOD access to a trusted wireless network, the engineer should implement NAC (Network Access Control). In the Network+ (N10-009) objectives, 802.1X provides authentication (commonly via EAP to a RADIUS server), but NAC expands this by enforcing policy-based access decisions—such as device posture checks, user/device identity validation, and dynamic assignment to the appropriate VLAN/role. With BYOD, the organization often needs to confirm whether devices meet requirements (OS version, encryption, security software) and then grant the correct level of access (full, limited, or quarantine/remediation). NAC is the architecture that ties these controls together in a scalable way for wireless networks.

An ACL can restrict traffic after a device connects, but it doesn’t perform authentication/posture assessment. MAC filtering is weak because MAC addresses can be spoofed and it does not provide strong identity assurance. Port security is mainly a wired switch control (limiting MAC addresses per port) and is not the right control set for secure BYOD wireless access. NAC best matches the requirement of secure, policy-driven 802.1X BYOD access.

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The answer is C. Multicast . The address 224.7.8.99 falls within the IPv4 Class D range, which is 224.0.0.0 through 239.255.255.255 . That range is reserved for multicast traffic. Multicast is used when one sender needs to deliver traffic to a specific group of receivers rather than to every device on the network or to just one destination.

That is what separates it from the other choices. Broadcast is intended for all hosts on the local broadcast domain. Unicast is one-to-one communication, where a single source sends traffic to one specific destination. Anycast is typically associated with sending traffic to the nearest or best member of a group that shares the same address, not to a multicast group address in the 224.0.0.0/4 range.

From a Network+ point of view, this is a basic address-recognition question. Once you recognize that the destination begins with 224 , the answer should immediately point to multicast. Protocols and streaming applications often use multicast when they need efficient delivery to multiple interested hosts without flooding every device. So in this case, the traffic type is clearly multicast .

The best answer is B. 255.255.252.0 , which is a /22 mask. A Class B network starts with a default mask of 255.255.0.0 or /16 . The question says the administrator wants four equal subnets , which means borrowing 2 bits from the host portion, since 2 borrowed bits gives 2² = 4 subnets . That moves the mask from /16 to /18 if subnetting is based only on splitting the Class B into four equal parts.

However, the answer choices point toward the host requirement as the deciding factor. Each subnet needs to support about 1,000 hosts . A /22 leaves 10 host bits , which gives 2¹⁰ = 1024 total addresses , or 1022 usable hosts after subtracting the network and broadcast addresses. That fits the requirement. Among the options provided, 255.255.252.0 is the only mask that supports around 1,000 hosts per subnet.

The smaller masks, /24 and /25 , do not allow enough hosts. The default Class B mask, /16 , does not subnet the network at all. Based on the available choices and the host-capacity requirement, 255.255.252.0 is the correct exam answer.

SSO (Single Sign-On) allows an organization to use an identity provider (IdP) to centrally manage authentication and access across multiple SaaS applications. In the Network+ (N10-009) objectives, identity and access management concepts include federated authentication, centralized account control, and reducing password sprawl. With SSO, users authenticate once to the IdP, and the IdP then provides assertions/tokens to SaaS services (commonly using federation standards such as SAML or OIDC in real environments). This improves security (fewer reused passwords, easier MFA enforcement), streamlines user experience, and simplifies administration (provisioning/deprovisioning from one place).

PKI supports certificates and encryption/signing, but it is not the core mechanism for managing access across many SaaS apps via an IdP. TACACS+ is typically used for device administration (AAA) on network equipment, and RADIUS commonly supports network access (802.1X, VPN) AAA—both are important AAA protocols but do not describe the SaaS-wide “one login across many apps” capability. Therefore, SSO is the best answer.

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EIGRP (Enhanced Interior Gateway Routing Protocol) has a default administrative distance (AD) value of 90 for internal routes. The administrative distance is used to rate the trustworthiness of routing information received from different routing protocols. EIGRP, developed by Cisco, has an AD of 90, which is lower than that of RIP (120) and OSPF (110), making it more preferred if multiple protocols provide a route to the same destination.References: CompTIA Network+ study materials.

The correct answer is PAT (Port Address Translation). According to the CompTIA Network+ N10-009 objectives, PAT is a form of Network Address Translation (NAT) that allows multiple internal hosts—or services—to be mapped to a single public IP address using different port numbers. PAT can also translate destination port numbers, which is exactly what is occurring in this scenario.

In this case, the firewall receives incoming traffic on port 80 (commonly used for HTTP) and forwards it to an internal server listening on port 88. This process is often referred to as port forwarding, which is a practical implementation of PAT. The firewall rewrites the destination port and potentially the destination IP address so that external clients can access internal services without exposing internal addressing schemes.

The other options do not apply. TLS and SSL are encryption protocols used to secure data in transit; they do not perform port translation. FHRP (First Hop Redundancy Protocol), such as HSRP or VRRP, provides gateway redundancy and high availability, not traffic forwarding or port remapping.

The Network+ objectives emphasize understanding how firewalls and NAT technologies manipulate IP addresses and ports to enable secure access to internal resources. PAT is the technology that enables this functionality, making it the correct answer.

The correct choice is B. Captive portal . This is the common setup used in places like libraries, hotels, airports, and cafés. A user first joins the wireless network, opens a browser, and is redirected to a web page where they must log in, accept terms, or enter provided credentials. Since the question specifically mentions authentication through HTTPS , that matches the behavior of a captive portal very closely.

The other options do not line up with the scenario. WPA3 is a wireless encryption and authentication standard, but it is not the same as a browser-based login page after connection. Single sign-on and SAML are identity and federation technologies used to simplify authentication across applications or services, not to provide the typical guest Wi-Fi web login experience.

The important clue is the sequence described in the question: first connect to Wi-Fi, then authenticate through a web page. That is exactly how a captive portal works. In many public-access wireless environments, the portal sits between the client and normal internet access until the user successfully authenticates or accepts the usage policy. For Network+ exam purposes, browser-based guest wireless authentication is most directly associated with a captive portal .

The right answer is A. Trap . In SNMP, a trap is an unsolicited notification sent from a managed device to the management system when a significant event happens. A switch detecting that an interface has gone up or down is a textbook example of the kind of event that can trigger this kind of message.

That is different from normal SNMP polling, where the monitoring server asks the device for status information on a schedule. With a trap, the device does not wait to be asked. It sends the alert immediately, which makes it useful for link failures, threshold violations, and other time-sensitive conditions.

The other choices are related to SNMP, but not in the same way. An object identifier (OID) points to a specific managed value. A string is commonly associated with SNMP community information in older versions. A MIB is the structured database of manageable objects. None of those are the actual alerting mechanism.

Because the question asks for an automatic alert when link status changes, the feature being described is clearly an SNMP trap .

Network Health:

WAN 2 appears to have a lower average latency and loss percentage, which would make it the preferred WAN station for VoIP traffic. VoIP traffic requires low latency and packet loss to ensure good voice quality and reliability. WAN 1 seems to have higher RAM and processor usage, which could also affect the performance of VoIP traffic.

Here ' s the summary of the key metrics for WAN 1 and WAN 2 from the image provided:

WAN 1:

Uplink Speed: 10G

Total Usage: 26.969GB Up / 1.748GB Down

Average Throughput: 353MBps Up / 23.42MBps Down

Loss: 2.51%

Average Latency: 24ms

Jitter: 9.5ms

WAN 2:

Uplink Speed: 1G

Total Usage: 930GB Up / 138GB Down

Average Throughput: 12.21MBps Up / 1.82MBps Down

Loss: 0.01%

Average Latency: 11ms

Jitter: 3.9ms

For VoIP traffic, low latency and jitter are particularly important to ensure voice quality. While WAN 1 has higher bandwidth and throughput, it also has higher latency and jitter compared to WAN 2. However, WAN 2 has much lower loss, lower latency, and lower jitter, which are more favorable for VoIP traffic that is sensitive to delays and variation in packet arrival times.

Given this information, WAN 2 would generally be preferred for VoIP traffic due to its lower latency, lower jitter, and significantly lower loss percentage, despite its lower bandwidth compared to WAN 1. The high bandwidth of WAN 1 may be more suitable for other types of traffic that are less sensitive to latency and jitter, such as bulk data transfers.

Device Monitoring:

the device that is experiencing connectivity issues is the APP Server or Router 1, which has a status of Down. This means that the server is not responding to network requests or sending any data. You may want to check the physical connection, power supply, and configuration of the APP Server to troubleshoot the problem.

A screenshot of a computer AI-generated content may be incorrect.

When a new VLAN is created, it typically exists on a different subnet. If DHCP servers are on a different VLAN, the network needs an IP helper address to forward DHCP requests correctly. Without it, clients in the new VLAN won’t receive an IP address.

Breakdown of Options:

A. Scope size – Increasing the DHCP scope would not resolve the issue if requests aren ' t reaching the server.

B. Address reservations – Reservations only assign specific addresses to devices; they do not fix DHCP communication issues.

C. Lease time – Changing the lease time does not impact DHCP functionality across VLANs.

D. IP helper – Correct answer. This forwards DHCP requests across VLANs to the DHCP server.

Port 22 is used for SFTP (Secure File Transfer Protocol) and SCP (Secure Copy Protocol), which encrypt file transfers using SSH (Secure Shell). This ensures data is transmitted securely over the network.

•Why not the other options?

•Port 69 (B) – TFTP (Trivial File Transfer Protocol): Transfers files but is not secure (no encryption).

•Port 80 (C) – HTTP: Used for web traffic, not for file transfer.

•Port 3389 (D) – RDP (Remote Desktop Protocol): Used for remote desktop access, not file transfer.

DHCP snooping is a security feature on network switches that helps to prevent unauthorized (rogue) DHCP servers from assigning IP addresses to clients. By implementing DHCP snooping, the network administrator can restrict DHCP responses to authorized servers only, preventing unauthorized DHCP configurations, such as incorrect DNS IPs, from being assigned to clients. This helps prevent man-in-the-middle attacks where malicious actors misconfigure DNS to redirect users to fraudulent sites. (Reference: CompTIA Network+ Study Guide, Chapter on Network Security)

The correct answer is OSPF (Open Shortest Path First). OSPF is a link-state routing protocol known for its fast convergence and use of the Dijkstra algorithm to calculate the shortest loop-free path. It efficiently scales to large enterprise networks and avoids routing loops by maintaining a complete topology map.

A. BGP is primarily an external routing protocol used between ISPs, not internal.

B. STP is not a routing protocol; it prevents loops at Layer 2.

D. RIP is an older distance-vector protocol with slower convergence and a maximum hop limit of 15.

OSPF’s design makes it the preferred internal gateway protocol (IGP) for medium-to-large organizations requiring speed and loop-free reliability.

References (CompTIA Network+ N10-009):

Domain: Networking Concepts — IGPs, OSPF, routing protocols.

Switches in sealed enclosures are at risk of overheating because airflow is restricted. The temperature factor is critical since heat buildup can damage components, shorten device lifespan, and cause outages. Proper cooling or ventilation must be ensured.

A. Fire suppression is important for data centers but not the primary concern in a sealed box.

B. Power budget applies to PoE allocations, not environmental safety.

D. Humidity matters, but overheating is far more immediate in sealed environments.

References (CompTIA Network+ N10-009):

Domain: Network Infrastructure — Environmental considerations, switch installation, temperature control.

SIEM (Security Information and Event Management) systems are used to aggregate and analyze log data from various sources, including firewalls, to detect potential security incidents and assist in regulatory compliance. The document explains:

“SIEM solutions aggregate and analyze log and event data from multiple devices, including firewalls, across different locations. They help in real-time monitoring, incident response, and ensuring compliance with security policies.”

VXLAN (Virtual Extensible LAN) encapsulates Ethernet frames inside UDP packets, increasing packet size. This can lead to fragmentation and performance degradation unless Jumbo Frames are enabled.

Breakdown of Options:

A. 802.1Q tagging – VLAN tagging enables segmentation but does not address fragmentation issues.

B. Spanning tree – STP prevents loops but does not improve performance for VXLAN traffic.

C. Link aggregation – LACP combines links for higher bandwidth but does not prevent fragmentation.

D. Jumbo frames – Correct answer. Enabling Jumbo Frames allows larger packet sizes, reducing fragmentation and improving VXLAN performance.