CompTIA N10-009 - CompTIA Network+ Certification Exam

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.

Servers shut down due to overheating, not loss of electrical power. Although UPS units had battery life, without cooling systems (HVAC/air conditioning) running on backup power, server rooms overheated. Backup power for air-conditioning is essential in data center design.

B. Door locks are unrelated to server shutdown.

C. Increasing UPS capacity won’t help cooling.

D. IoT thermostats may monitor temperature but won’t prevent overheating.

References (CompTIA Network+ N10-009):

Domain: Network Infrastructure — Environmental controls, power redundancy, HVAC systems.

Switch 1

spanning-tree vlan 10 root primary

spanning-tree vlan 20 root secondary

Switch 2

spanning-tree vlan 20 root primary

spanning-tree vlan 10 root secondary

This PBQ is pointing to a switching loop / MAC flapping problem. The biggest clues are the high CPU utilization and the fact that the MAC table is continuously changing . That behavior is classic for a Layer 2 loop when redundant links exist between switches and no proper spanning-tree root role has been established.

The available commands shown in the screenshots are limited to spanning-tree vlan , so this is not an interface shutdown question. The fix is to use STP per VLAN and make one switch the preferred root for one VLAN and the other switch the preferred root for the other VLAN. That prevents both uplinks from forwarding in an uncontrolled loop while still giving redundancy.

A clean design is:

Switch 1 root primary for VLAN 10

Switch 2 root primary for VLAN 20

Make each opposite switch root secondary for failover

That stabilizes Layer 2 forwarding, stops MAC address flapping, reduces CPU load, and restores normal connectivity. After applying the STP root settings, the user should be able to ping 192.168.1.31 from PC 1 successfully. If your simulator asks for validation, run the ping again from PC 1 to the database server.

The correct metric is RTO (Recovery Time Objective). RTO defines the maximum acceptable time to restore services after a disruption, ensuring business continuity. For example, if the RTO is 4 hours, systems must be back online within that timeframe after an outage.

B. MTBF (Mean Time Between Failures) measures reliability by calculating the average time between hardware failures.

C. RPO (Recovery Point Objective) defines how much data loss (in terms of time, such as last backup point) is acceptable.

D. MTTR (Mean Time to Repair) measures the average time taken to fix a failure but is not a predefined business requirement like RTO.

Organizations define RTOs during disaster recovery planning to align IT recovery capabilities with business needs.

References (CompTIA Network+ N10-009):

Domain: Networking Concepts — Business continuity metrics (RTO, RPO, MTBF, MTTR).

VLANs (Virtual Local Area Networks) segment network traffic by department, allowing ACLs (Access Control Lists) to be applied based on VLAN membership, improving security and resource isolation.

Breakdown of Options:

A. VLAN – Correct answer. VLANs enable logical network segmentation, allowing ACLs per department.

B. DHCP – Assigns IP addresses but does not control access.

C. VPN – Provides remote access, not segmentation within a network.

D. STP – Prevents switching loops, not related to ACL implementation.

The problem is a subnet mismatch . The web server is using 255.255.255.0 , which places it in the 192.168.1.0/24 network. The database server is using 255.255.255.128 , which places 192.168.1.201 in the 192.168.1.128/25 network. So even though both addresses begin with 192.168.1, the two systems are not treating the network boundaries the same way.

That creates a Layer 3 communication issue because one host may believe the other device is local while the other host may treat traffic differently based on its smaller subnet. In a normal server segment like this, both systems should agree on the same mask if they are intended to be on the same network.

Changing the database server’s subnet mask to 255.255.255.0 fixes that inconsistency immediately. Then both servers and the firewall interface are using the same local network definition, and traffic can be handled properly.

The other options do not solve the real issue. Changing the firewall to /25 would break consistency for the rest of the segment. Pointing the database server to 1.2.3.4 is incorrect because that is outside the local subnet and appears to be an upstream route. Changing the IP to 192.168.1.150 still leaves the wrong mask in place. The clean fix is A .

If the administrator is concerned a new discovery tool could disrupt operations, the safest option is to configure scheduled scans. Network+ (N10-009) operations guidance emphasizes minimizing impact by running potentially noisy tasks (discovery, vulnerability checks, inventory scans) during defined maintenance windows or off-peak hours. A scheduled scan allows controlled timing, predictable load, and easier coordination with change management, monitoring, and support teams. This reduces the risk of saturating links, overwhelming devices with queries, or triggering alerts during business-critical periods.

Ad hoc scanning is on-demand and may occur at any time, which increases the chance of disruption if run during peak usage. Authenticated versus unauthenticated describes whether the scanner uses credentials to log into systems for deeper visibility; that choice affects depth and accuracy, but it doesn’t directly address when scanning occurs to reduce business impact. An authenticated scan can still be disruptive if run at the wrong time, and an unauthenticated scan can still generate significant traffic. Since the key concern is operational disruption, controlling scan timing via scheduled scans is the best mitigation.

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Port 443 is used by HTTPS (Hypertext Transfer Protocol Secure), a secure version of HTTP that uses SSL/TLS to encrypt the communication between a client and server. This ensures confidentiality and integrity of data in transit. The document states:

“Port 443 is the default port for HTTPS, which secures HTTP traffic using SSL/TLS, providing encryption and secure identification of web servers.”

It is common for an access port to have both a voice VLAN and a data VLAN. A voice VLAN separates voice traffic from regular data traffic, ensuring better quality and security for voice communications.

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The 802.11n standard supports MIMO (Multiple Input Multiple Output), which allows multiple antennas to increase data throughput and improve reliability. Additionally, it uses non-overlapping channels in the 5 GHz band (and optionally the 2.4 GHz band), making it a good choice for high-speed, interference-resistant wireless connections. (Reference: CompTIA Network+ Study Guide, Chapter on Wireless Technologies)

In a data center that uses hot aisle/cold aisle ventilation, equipment is typically installed so that cool air enters from the cold aisle (front) and hot air is exhausted to the hot aisle (rear). This configuration maximizes cooling efficiency.

A honeypot is specifically designed to attract, isolate, and observe malicious activity so defenders can learn how an attacker is operating and determine attack techniques. In the context of Network+ (N10-009) security objectives, honeypots (and broader deception technologies) are defensive controls used to detect reconnaissance and exploitation attempts by presenting a decoy system or service that appears legitimate. Because a honeypot should not receive normal production traffic, any interaction is suspicious, making it valuable for identifying threat actors, collecting indicators of compromise, and analyzing the attacker’s tools, commands, and behavior patterns. This supports the goal of understanding the type of attack used (for example, credential stuffing, exploitation attempts, lateral movement probes) while keeping the attacker away from real assets.

MFA strengthens authentication but does not provide a controlled environment to observe attacker techniques. A screened subnet (DMZ) is for segmentation of public-facing services and reducing exposure of internal systems, but it is not primarily used to “bait” and analyze attackers. A captive portal enforces user acknowledgement/authentication for network access; it is not a deception/analysis system. Therefore, honeypot is the best match.

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The correct answer is Static because static routes have a lower administrative distance (AD) than most dynamic routing protocols, giving them higher priority when a router selects routes for the same destination network. According to CompTIA Network+ (N10-009) routing objectives, administrative distance is used to determine the trustworthiness of a route source when multiple routing protocols provide a path to the same subnet. The lower the administrative distance, the more preferred the route.

By default, a static route has an administrative distance of 1, which is lower than OSPF (110) and BGP (20 for eBGP, 200 for iBGP). Because of this, when identical routes to a subnet exist from both static and dynamic sources, the router installs the static route in the routing table.

A default route (0.0.0.0/0) is only used when no more specific route exists and does not take precedence over specific static or dynamic routes.

Therefore, when building the routing table for a given subnet and comparing route sources, static routes take precedence due to their lower administrative distance.

Enterprise authentication (such as WPA2-Enterprise) utilizes unique credentials for each user, typically integrating with an authentication server like RADIUS. This allows for tracking and logging user activity, ensuring that all connections can be traced back to individual users. PSKs (Pre-Shared Keys) are shared among users and do not provide individual accountability. Captive portals can identify users but are less secure than enterprise authentication, and Wired Equivalent Privacy (WEP) is outdated and not recommended for security purposes.

Malware refers to any malicious software that can exfiltrate confidential data, including spyware, trojans, and rootkits. This fits the scenario where unauthorized data transfer is occurring.

Breakdown of Options:

A. Adware – Displays ads, does not typically steal data.

B. Ransomware – Encrypts files but does not exfiltrate data.

C. Darkware – Not a real cybersecurity term.

D. Malware – Correct answer. Malicious software is responsible for unauthorized data exfiltration.