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

Spanning Tree Protocol (STP) uses bridge priority values to determine the root bridge in a switched network topology. Correctly configuring bridge priority helps in maintaining a loop-free and efficient network. The document explains:

“Spanning Tree Protocol (STP) uses bridge priority values to determine which switch will be the root bridge, ensuring loop prevention and efficient path selection within the network.”

•A. Isolate smart devices to their own network segment: Network segmentation using VLANs or separate SSIDs ensures that smart devices (like speakers) are not on the same network as guests, preventing unauthorized control.

•E. Change the default credentials: Many IoT devices (e.g., smart speakers) come with default usernames and passwords. If these are not changed, unauthorized users can easily take control.

•Why not the other options?

•B. Configure IPS: IPS (Intrusion Prevention System) detects threats but cannot block specific guest actions on an IoT device.

•C. Install a new AP: A new access point does not solve the unauthorized control issue.

•D. Set up a syslog server: Helps with logging, but does not prevent unauthorized access.

•F. Configure GRE: Generic Routing Encapsulation (GRE) is used for VPN tunneling, which is irrelevant in this case.

The correct answer is ACL (Access Control List). According to the CompTIA Network+ N10-009 objectives, ACLs are a fundamental and cost-effective method for controlling traffic flow at routers and firewalls. An ACL allows administrators to permit or deny traffic based on source IP address, destination IP address, protocol, or port number.

In this scenario, the suspicious traffic is identified as originating from a specific unknown foreign IP address. The most direct and economical mitigation strategy is to configure an ACL rule that denies traffic from that specific IP address (or subnet) at the network perimeter. This approach leverages existing network infrastructure without requiring additional hardware or licensing costs.

An IDS (Intrusion Detection System) monitors and alerts on malicious activity but does not actively block traffic unless paired with IPS functionality, and it may involve additional cost and complexity. NAT is used for address translation and does not provide traffic filtering based on threat intelligence. DoS prevention solutions are typically more advanced, specialized, and costly, often intended for large-scale distributed denial-of-service attacks rather than blocking traffic from a single suspicious IP.

The Network+ objectives emphasize implementing layered security controls, starting with simple and effective measures. In this case, applying an ACL at the firewall or router is the most cost-efficient and immediate method to mitigate the identified threat.

Disabling unused ports prevents unauthorized access and reduces the attack surface by ensuring that no inactive or unmonitored entry points are available for exploitation. Changing default passwords is critical for security because default credentials are widely known and can easily be exploited by attackers. These techniques are fundamental steps in hardening devices against unauthorized access and ensuring network security. References: CompTIA Network+ Exam Objectives and official study guides.

Link aggregation(also known as port channeling or EtherChannel) allows multiple physical connections to act as one logical connection. This avoids loops that would typically be prevented by STP and provides redundancy and increased bandwidth. It ' s ideal when STP is not available or desirable.

The correct answer is Modify the CNAME record because a CNAME (Canonical Name) record maps one domain name (alias) to another domain name. If a user enters www.abc.com but is redirected to www.cba.com, it is likely that the DNS configuration includes an incorrect CNAME entry pointing abc.com to cba.com. Updating or correcting the CNAME record ensures the alias resolves to the intended host.

According to CompTIA Network+ (N10-009) objectives covering DNS record types, a CNAME record is used to alias one domain name to another, commonly for load balancing, CDN services, or website redirection.

A PTR record (Option B) is used for reverse DNS lookups (IP address to hostname) and does not control forward name resolution for websites. NTP settings (Option C) are used for time synchronization and have no impact on DNS resolution. A TXT record (Option D) stores descriptive text information (such as SPF, DKIM, or domain verification data) and does not affect website redirection.

Therefore, correcting the CNAME record resolves the issue and ensures users reach the correct website.

A split-tunnel VPN allows certain traffic (e.g., cloud-based services) to bypass the VPN and go directly to the Internet. This reduces the amount of traffic that needs to traverse the company ' s VPN and Internet connection, conserving bandwidth and reducing costs. It also means that not all traffic is subject to the same level of inspection or filtering, which can improve performance for cloud-based services.References: CompTIA Network+ study materials.

(Note: Ips will be change on each simulation task, so we have given example answer for the understanding)

To perform a network discovery by entering commands into the terminal, you can use the following steps:

Click on each switch to open its terminal window.

Enter the command show ip interface brief to display the IP addresses and statuses of the switch interfaces.

Enter the command show vlan brief to display the VLAN configurations and assignments of the switch interfaces.

Enter the command show cdp neighbors to display the information about the neighboring devices that are connected to the switch.

Fill in the missing information in the diagram using the drop-down menus provided.

Here is an example of how to fill in the missing information for Core Switch 1:

The IP address of Core Switch 1 is 192.168.1.1.

The VLAN configuration of Core Switch 1 is VLAN 1: 192.168.1.0/24, VLAN 2: 192.168.2.0/24, VLAN 3: 192.168.3.0/24.

The neighboring devices of Core Switch 1 are Access Switch 1 and Access Switch 2.

The interfaces that connect Core Switch 1 to Access Switch 1 are GigabitEthernet0/1 and GigabitEthernet0/2.

The interfaces that connect Core Switch 1 to Access Switch 2 are GigabitEthernet0/3 and GigabitEthernet0/4.

You can use the same steps to fill in the missing information for Access Switch 1 and Access Switch 2.

DNS poisoning (also commonly called DNS cache poisoning) is characterized by inserting fraudulent DNS data into a resolver’s cache so that subsequent queries return incorrect IP mappings. Option D describes this precisely: false DNS records are injected into a DNS server’s cache, causing users to be redirected to attacker-controlled destinations even when they request a legitimate hostname. This aligns with Network+ security objectives covering common network attacks targeting name resolution and trust relationships. Editing authoritative DNS records on a DNS server (A) implies direct compromise or unauthorized administrative change, which is a different scenario than cache poisoning. Setting up a malicious DNS server in place of a legitimate server (B) is closer to DNS hijacking or rogue DNS configuration rather than cache poisoning. Intercepting client requests and returning false responses (C) describes man-in-the-middle style spoofing on the wire; while related, the defining “poisoning” trait is the persistence created by corrupting the cache so the bad answer continues to be served. For defensive relevance in Network+ scope, cache poisoning highlights the importance of DNS security controls such as source port randomization, transaction ID entropy, and DNSSEC validation where applicable.

802.1X is a port-based network access control (PNAC) protocol that provides an authentication mechanism to devices wishing to connect to a LAN or WLAN. It is widely used for secure network access, ensuring that only authenticated devices can access the network, whether they are connecting via wired or wireless means. 802.1X works in conjunction with an authentication server, such as RADIUS, to validate the credentials of devices trying to connect.References: CompTIA Network+ study materials.

MTTR (Mean Time to Repair) is the average time it takes to repair a system or service after a failure. It helps in measuring the downtime and planning recovery processes.

=================

A modern replacement for traditional remote-access VPN for users is SASE (Secure Access Service Edge). Network+ highlights trends in remote connectivity and security where organizations move away from backhauling all user traffic through a VPN concentrator and instead use cloud-delivered security and access controls closer to the user. SASE combines networking and security capabilities—commonly including ZTNA (Zero Trust Network Access), secure web gateway (SWG), CASB, firewall-as-a-service (FWaaS), and centralized policy enforcement—so remote users can securely access applications without relying on a classic “connect to the corporate network first” VPN model.

SD-WAN primarily optimizes connectivity between sites and to cloud services, often for branch networks; it’s not typically the direct replacement for remote user VPN access. Site-to-site VPN connects networks (locations) and is not intended for individual remote users. A reverse proxy can publish specific internal web applications externally and provide some security functions, but it does not replace VPN broadly for remote user access to multiple internal resources the way SASE/Zero Trust access solutions do. Therefore, SASE is the best answer as the likely replacement for traditional remote-access VPN.

Cross talk can often be caused by improper termination of cables. The first step in troubleshooting should be to inspect the connectors for any wires that might be touching or exposed. Ensuring that all wires are correctly seated and that no conductors are exposed can help reduce or eliminate cross talk. This step should be taken before attempting to re-terminate the connections or check for other sources of interference.References: CompTIA Network+ study materials.

The correct answer is traceroute, which is the diagnostic command specifically designed to determine the path a packet takes across a network. According to the CompTIA Network+ N10-009 objectives, traceroute is a key network troubleshooting tool used to identify routing paths, hop counts, and points of latency or failure between a source and a destination.

Traceroute works by sending packets with incrementally increasing Time to Live (TTL) values. Each router along the path decrements the TTL by one, and when it reaches zero, the router returns an ICMP Time Exceeded message. This process allows the administrator to see each intermediate hop, its response time, and where packets may be delayed or dropped.

The other options do not fulfill this purpose. Ping only verifies basic connectivity and round-trip time but does not show the route taken. Netstat displays active connections, ports, and routing tables but does not trace packet paths. Nslookup is used to resolve DNS names to IP addresses, and ipconfig displays local network configuration information.

The Network+ objectives emphasize traceroute (or tracert on Windows systems) as the primary tool for diagnosing routing issues, asymmetric paths, and network congestion, making it the correct and most appropriate choice in this scenario.

If the three new employees can communicate with each other’s devices, that strongly suggests their local Layer 2/Layer 3 connectivity is working (same VLAN/subnet, switching is fine, and they have IP addressing that allows local communication). The fact that they cannot access company resources (often on other subnets, servers, or the internet via internal routing) points to a problem with how these new endpoints are being addressed or routed beyond their local segment.

The most likely shared root cause affecting only “new employees” is DHCP scope/pool configuration. If the DHCP pool is exhausted, mis-scoped, or handing out incorrect options (such as an incorrect default gateway, wrong subnet mask, or an address range tied to an isolated VLAN), users could still talk locally but fail to reach resources outside their subnet. Modifying the DHCP server pool (expanding the scope, correcting the scope network, or ensuring the correct options are assigned) would resolve this with minimal changes.

A gateway routing table issue would typically affect many users, not just three new ones. DNS misconfiguration on the router would more commonly cause name-resolution problems, not block all resource access (and wouldn’t be isolated to only new employees). A workstation firewall would not usually prevent access to “company resources” in a way that consistently affects three new devices while still allowing peer connectivity.

If APs are changing channels frequently, it indicates automatic channel selection due to interference. This can cause temporary disconnections as the APs switch frequencies.

Breakdown of Options:

A. Channel interference – ✅ Correct answer. APs change channels automatically to avoid interference, causing disconnections.

B. Roaming misconfiguration – Roaming only affects moving users, but users report issues while stationary.

C. Network congestion – Causes slow speeds, not frequent disconnects.

D. Insufficient wireless coverage – Would cause weak signals, but not channel switching issues.

Elasticity is the ability of a system (often in cloud environments) to automatically scale resources up or down in real time based on demand.

A. Scalability means the ability to grow over time but not necessarily dynamically.

B. SaaS is a service model, not a resource-allocation concept.

C. Hybrid cloud is a deployment model, not a performance behavior.

References (CompTIA Network+ N10-009):

Domain: Networking Concepts — Cloud computing, elasticity vs. scalability.

X.509 certificates are most commonly associated with Public Key Infrastructure (PKI). These certificates are used for a variety of security functions, including digital signatures, encryption, and authentication.

PKI: X.509 certificates are a fundamental component of PKI, used to manage encryption keys and authenticate users and devices.

Digital Certificates: They are used to establish secure communications over networks, such as SSL/TLS for websites and secure email communication.

Authentication and Encryption: X.509 certificates provide the means to securely exchange keys and verify identities in various applications, ensuring data integrity and confidentiality.

Network References:

CompTIA Network+ N10-007 Official Certification Guide: Covers PKI and the role of X.509 certificates in network security.

Cisco Networking Academy: Provides training on PKI, certificates, and secure communications.

Network+ Certification All-in-One Exam Guide: Explains PKI, X.509 certificates, and their applications in securing network communications.

API gateways offer programmable control and real-time communication, commonly over HTTPS, which allows administrators to update and manage devices like access points remotely and efficiently.

From Andrew Ramdayal’s guide:

“APIs enable automation and real-time interaction with network devices via secure interfaces, often using HTTPS for encrypted communication and control.”

The correct answer is SaaS (Software as a Service). According to the CompTIA Network+ N10-009 objectives, SaaS is the most cost-efficient cloud model for hosting common business applications such as email, collaboration tools, and productivity suites. With SaaS, the cloud provider manages all infrastructure, operating systems, application software, security updates, and maintenance, significantly reducing administrative overhead and operational costs.

Email services are a prime example of workloads that benefit from SaaS solutions such as Microsoft 365 or Google Workspace. Organizations pay a subscription-based fee, typically per user, and avoid expenses related to server hardware, licensing, patching, backups, redundancy, and disaster recovery. This makes SaaS far more economical than deploying and maintaining email servers internally or in lower-level cloud models.

IaaS requires the organization to manage virtual machines, operating systems, email server software, and security configurations, which increases both cost and complexity. PaaS simplifies application development but is not designed for hosting ready-made services like email platforms. A VPC (Virtual Private Cloud) is a networking construct, not a service model, and does not inherently provide email hosting functionality.

The Network+ objectives emphasize selecting cloud service models based on cost, management responsibility, and operational efficiency. For standardized services like email, SaaS offers the lowest total cost of ownership and the least administrative burden, making it the best and most cost-effective choice.

Definition of a Rogue DHCP Server:

A rogue DHCP server is an unauthorized DHCP server on a network, which can assign IP addresses to devices without proper control, leading to IP address conflicts.

Impact of a Rogue DHCP Server:

IP Address Conflicts: Multiple devices may receive the same IP address from different DHCP servers, causing network connectivity issues.

Network Disruption: Devices may be assigned incorrect network configuration settings, disrupting network services and connectivity.

Comparison with Other Attacks:

DNS poisoning: Alters DNS records to redirect traffic to malicious sites, but does not cause IP address conflicts.

Social engineering: Involves manipulating individuals to gain unauthorized access or information, not directly related to IP address conflicts.

Denial-of-service (DoS): Floods a network or service with excessive traffic to disrupt operations, but does not cause duplicate IP addresses.

Prevention and Detection:

Implement network access control measures to prevent unauthorized devices from acting as DHCP servers.

Use DHCP snooping on switches to allow DHCP responses only from authorized DHCP servers.

Multi-factor authentication (MFA) requires two or more different categories of authentication factors:

Something you know (password, PIN)

Something you have (smart card, hardware token)

Something you are (biometric)

The only valid second factor here is a hard token (e.g., a key fob generating one-time codes).

A. PIN is still “something you know,” the same category as a password.

B. Favorite color is a weak knowledge-based factor, not a true second factor.

D. Mother’s maiden name is also “something you know” and insecure.

References (CompTIA Network+ N10-009):

Domain: Network Security — Authentication methods, MFA factor categories.

When working with fiber optic cables, one common issue is that the transmit (TX) and receive (RX) fibers might be reversed. The first step in troubleshooting should be to reverse the fibers at one end to ensure they are correctly aligned (TX to RX and RX to TX). This is a simple and quick step to rule out a common issue before moving on to more complex troubleshooting.References: CompTIA Network+ study materials.

Port mirroring, also known as SPAN (Switched Port Analyzer), is used to send a copy of network packets seen on one switch port (or an entire VLAN) to another port where the IDS is connected. This allows the IDS to passively inspect network traffic without interfering with the actual traffic flow. Port mirroring is an essential feature for implementing IDS in a network for traffic analysis and security monitoring.References: CompTIA Network+ study materials.

An Extended Service Set Identifier (ESSID) allows multiple access points to share the same SSID, enabling seamless roaming for users. This means that users can move between different access points within the same ESSID without losing connection or having to reauthenticate. This provides a better user experience, especially in large environments such as office buildings or campuses.References: CompTIA Network+ study materials. ​

The correct answer is D. DHCP reservation. In a network environment, printers are typically configured to use a consistent IP address so that client devices can reliably locate them. After a power outage, network devices such as printers may reboot and request a new IP address from the DHCP server. If the printer was previously assigned a dynamic IP address, it may now receive a different address, causing users’ systems to lose connectivity because they are still trying to print to the old IP.

A DHCP reservation ensures that a specific device (identified by its MAC address) always receives the same IP address from the DHCP server. This combines the convenience of DHCP with the stability of static addressing, which is ideal for shared resources like printers.

The other options are incorrect for this scenario. DoH (DNS over HTTPS) secures DNS queries and is unrelated to IP address assignment. SLAAC (Stateless Address Autoconfiguration) is used for IPv6, not IPv4 environments. APIPA (Automatic Private IP Addressing) assigns a link-local address when DHCP fails, but it does not provide consistent or routable addressing suitable for shared printers.

Therefore, configuring a DHCP reservation ensures consistent network access to the printer after power disruptions.

Understanding the Vulnerability:

Vulnerabilities in the router CPU can be exploited to cause performance degradation, unauthorized access, or other security issues.

Firmware Update:

Firmware Role: The firmware is low-level software that controls the hardware of a device. Updating the firmware can address vulnerabilities by providing patches and enhancements from the manufacturer.

Procedure: Download the latest firmware from the vendor’s website, follow the manufacturer ' s instructions to apply the update, and verify that the update resolves the vulnerability.

Comparison with Other Options:

Replace the System Board: This is a costly and often unnecessary step if the issue can be resolved with a firmware update.

Patch the OS: Patching the OS is relevant for devices with a full operating system but not directly applicable to addressing a CPU vulnerability on a router.

Isolate the System: Temporarily isolating the system can mitigate immediate risk but does not resolve the underlying vulnerability.

Best Practice:

Regularly check for and apply firmware updates to ensure that network devices are protected against known vulnerabilities.

Verifying full system functionality occurs after implementing a fix. This step ensures the solution resolved the issue and that performance is back to expected levels. Comparing current throughput to baseline measurements is part of validation testing to confirm everything is within normal operational parameters.

A. Implement the solution applies the fix but does not confirm results.

C. Document findings happens at the end of troubleshooting.

D. Test the theory comes earlier, when trying to confirm the suspected cause.

References (CompTIA Network+ N10-009):

Domain: Network Troubleshooting — Troubleshooting methodology steps, baselines, verification testing.

MIBs (Management Information Bases) define the variables and objects that SNMP can query on a device. If the monitoring server authenticates but cannot interpret the data, it likely lacks the correct MIB for that vendor or model. Importing the proper MIB allows the monitoring server to correctly display device status and metrics.

A. Using a public community string is insecure and not related to missing MIBs.

C. Switchport analyzer (SPAN) captures traffic for packet analysis, not SNMP monitoring.

D. SNMPv3 privacy adds encryption but doesn’t fix missing MIB interpretation.

References (CompTIA Network+ N10-009):

Domain: Network Operations — SNMP, MIBs, network monitoring systems.