Pass the CompTIA Network+ N10-009 Questions and answers with Dumpstech

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.

When a host fails to obtain an IP address from a DHCP server, it assigns itself an APIPA (Automatic Private IP Addressing) address in the 169.254.x.x range, commonly described as a “self-assigned IP.” This prevents communication outside the local link, including reaching the default gateway.

B. RFC1918 addresses are private ranges (10.x.x.x, 172.16–31.x.x, 192.168.x.x), but these are not self-assigned.

C. If the TCP/IP stack were disabled, the host wouldn’t have any IP at all.

D. If a static IP were assigned, it would show a configured value, not self-assigned.

References (CompTIA Network+ N10-009):

Domain: Network Troubleshooting — IP addressing issues, DHCP failures, APIPA behavior.

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.”

A Virtual Private Network (VPN) creates an encrypted connection between a remote user and an internal network, ensuring secure access to internal applications.

VPNs use encryption protocols like IPSec and SSL/TLS to protect data during transmission.

They are widely used for secure remote work, accessing company resources, and bypassing geographic restrictions.

Option B (CDN - Content Delivery Network): Used for speeding up website content delivery, not for remote access security.

Option C (SAN - Storage Area Network): Used for high-speed storage, unrelated to remote access.

Option D (IDS - Intrusion Detection System): Monitors for malicious activities but does not provide secure access to applications.

? Reference: CompTIA Network+ (N10-009) Official Study Guide – Section: Secure Remote Access Technologies

Power over Ethernet (PoE) delivers power to devices such as VoIP phones over the same cables used for data. If the total power requirement of connected devices exceeds the PoE power budget of the switch or injector, some devices may not receive adequate power and could intermittently reboot. This issue would not affect the workstation, which is likely receiving power separately. References: CompTIA Network+ Exam Objectives and official study guides.

The user’s inability to access the marketing department’s shared drives, despite having internet access, suggests a network segmentation issue. The most likely cause is an incorrect VLAN assignment. The computer is physically located on the accounting department floor, and the switchport is likely configured for the accounting VLAN, not the marketing VLAN. VLANs segment network traffic, and if the computer is in the wrong VLAN, it cannot communicate with the marketing department’s resources.

Why not Mismatched switchport duplex? Duplex mismatches cause performance issues (e.g., packet loss) but not specific access denials to shared drives.

Why not Misconfigured gateway settings? Incorrect gateway settings would prevent internet access, which the user has.

Why not SVI is assigned to the wrong IP address? A Switch Virtual Interface (SVI) with an incorrect IP address affects inter-VLAN routing, but this would likely impact multiple users, not just one.

When two devices on different subnets are unable to communicate, but can communicate with other devices on their own subnet, the issue is most often related to routing. Devices on different subnets require a default gateway to route traffic between networks.

If the default gateway is incorrectly configured, the device won’t know how to reach other subnets.

Faulty cables (Option B) or duplex mismatches (Option C) would likely cause connectivity issues even within the local subnet, which is not the case here.

VLAN mismatches (Option D) are typically issues with switch port configurations and would likely cause total loss of connectivity, including within the same subnet.

✅ So, the most probable and logical cause is an incorrect default gateway.

Comprehensive and Detailed Explanation (paraphrased, aligned to N10-009):

In a spine–leaf architecture, endpoints (including servers, firewalls, and WAN/edge routers) connect to leaf switches. Leaf switches then uplink to spine switches; spine switches do not have endpoints connected directly to them. Therefore, a WAN router (an external/edge device) should connect to the leaf layer—often specifically to a “border leaf” that handles external connectivity.

Why not B. Core or D. Spine? In spine–leaf, “core” isn’t a formal layer, and spines are designed only to interconnect leafs, not to terminate endpoints.

Why not A. Access? “Access” is a term from the traditional three-tier model (access–distribution–core). In modern spine–leaf language, the analogous layer for endpoint attachment is the leaf.

References (CompTIA Network+ N10-009):

Domain: Network Infrastructure — Data center and campus architectures (spine–leaf vs. three-tier), roles of leaf/spine, WAN/edge connectivity points.

===========

Unshielded cables (D) are more prone to interference and may not be suitable for certain environments, especially after a fire where interference could be heightened.

Using the wrong transceiver (E) for new terminations can lead to compatibility issues, causing network failures.

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

If the company’s SSID is not visible in some areas while other networks are still visible, the most likely cause is insufficient wireless coverage. The wireless signal does not reach those areas, meaning additional access points or signal boosters may be required.

Breakdown of Options:

A. Interference or channel overlap – Would cause slow or unstable connections, but the SSID should still be visible.

B. Insufficient wireless coverage – ✅ Correct answer. If the SSID is not appearing, the signal is too weak in that area.

C. Roaming misconfiguration – Would cause devices to stay on weaker APs instead of switching, but the SSID should still be visible.

D. Client disassociation issues – This would disconnect users, but they should still see the network.

Since the switch supports only 10Gbps per port, achieving 40Gbps throughput requires link aggregation (LACP), which combines multiple 10Gbps links into one logical interface for higher bandwidth.

Breakdown of Options:

A. 802.1Q tagging – VLAN tagging helps segment traffic but does not increase throughput.

B. Jumbo frames – Jumbo frames reduce overhead but do not increase bandwidth.

C. Half duplex – Half duplex restricts communication, reducing performance instead of improving it.

D. Link aggregation – Correct answer. LACP combines multiple 10Gbps links to provide a 40Gbps connection.

Introduction to Disaster Recovery Concepts:

Disaster recovery involves strategies and measures to ensure business continuity and data recovery in the event of a disaster.

Mean Time Between Failures (MTBF):

MTBF is a reliability metric used to predict the time between failures of a system during operation. It is calculated by dividing the total operational time by the number of failures.

Formula: MTBF=Total Operational TimeNumber of Failures\text{MTBF} = \frac{\text{Total Operational Time}}{\text{Number of Failures}}MTBF=Number of FailuresTotal Operational Time​

This metric helps in understanding the reliability and expected lifespan of systems and components.

Example Calculation:

If a server operates for 1000 hours and experiences 2 failures, the MTBF is: MTBF=1000 hours2=500 hours\text{MTBF} = \frac{1000 \text{ hours}}{2} = 500 \text{ hours}MTBF=21000 hours​=500 hours

Explanation of the Options:

A. MTTR (Mean Time to Repair): The average time required to repair a system after a failure.

B. MTBF (Mean Time Between Failures): The correct answer, representing the average time between failures.

C. RPO (Recovery Point Objective): The maximum acceptable amount of data loss measured in time.

D. RTO (Recovery Time Objective): The target time set for the recovery of IT and business activities after a disaster.

Conclusion:

MTBF is a crucial metric in disaster recovery and system reliability, helping organizations plan maintenance and predict system performance.

An IDS (Intrusion Detection System) is deployed out-of-band, meaning it passively monitors network traffic using a SPAN/mirror port or network tap. It detects and analyzes suspicious traffic without introducing latency since it does not sit in-line.

A. IPS (Intrusion Prevention System) is in-line and can block traffic but may add latency.

C. Load balancer distributes traffic across servers for performance and redundancy, not for threat detection.

D. Firewall filters traffic at the perimeter or internally; it can affect latency but does not provide the same in-depth attack analysis.

References (CompTIA Network+ N10-009):

Domain: Network Security — IDS vs. IPS, in-band vs. out-of-band monitoring, passive detection methods.

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.

•The total number of devices = (150 + 10) users × 2 IPs per user = 320 devices

•Class C (D) supports a maximum of 254 hosts (2^8 - 2), which is too small.

•Class B (B) supports 65,534 hosts (2^16 - 2), making it the best choice.

•Why not the other options?

•Class A (C): Supports millions of addresses, which is overkill for 320 devices.

•Class D (A): Used for multicast, not for device addressing.