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

Single-mode fiber is best suited for long-distance communication, often exceeding 10 km (6.2 miles). It's immune to EMI and offers high bandwidth — making it the ideal choice for connecting buildings across a city.

Coaxial (A) and Twinaxial (B) are used for shorter distances and specific use cases (e.g., storage or legacy systems).

Cat 5 (D) is limited to 100 meters and is not suitable for city-level interconnects.

✅ For long-distance, high-speed, and reliable communication between buildings, Single-mode fiber is the professional choice.

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.

The laptop is most likely using the 2.4GHz frequency band. According to the CompTIA Network+ N10-009 objectives, the 2.4GHz band is particularly susceptible to electromagnetic interference (EMI) from common household and office devices, including microwave ovens, cordless phones, Bluetooth devices, and baby monitors. Microwave ovens operate at approximately 2.45GHz, which overlaps directly with the 2.4GHz Wi-Fi spectrum. When the microwave is powered on, it emits interference that can significantly degrade or completely disrupt nearby wireless communications operating in this band.

The 5GHz and 6GHz bands operate at much higher frequencies and do not overlap with microwave emissions, making them far less prone to this type of interference. While higher-frequency bands have shorter range and lower wall penetration, they provide cleaner channels and improved performance in dense environments. The 900MHz band is not used by standard Wi-Fi networks defined in the Network+ objectives and is more commonly associated with legacy cordless phones and certain IoT or proprietary wireless technologies.

Network+ troubleshooting guidance emphasizes identifying environmental interference sources when diagnosing intermittent wireless connectivity. A common mitigation strategy is to migrate affected devices to the 5GHz or 6GHz bands or reposition access points away from interference sources like break room appliances.

A rogue DHCP server occurs when an unauthorized or misconfigured DHCP server assigns incorrect IP addresses, default gateways, or DNS settings to clients.

•In this scenario:

•The user can ping the gateway, meaning local network communication is working.

•However, they cannot access network resources, which suggests incorrect IP configuration (likely due to a rogue DHCP server assigning the wrong gateway or DNS).

•Why not the other options?

•VLAN hopping (A): This is an attack that exploits VLAN configurations to gain access to unauthorized VLANs. It would not typically cause multiple users to lose network access.

•Distributed DoS (C): A DDoS attack floods a network or service with traffic, but this issue is more likely misconfigured IP settings than an actual attack.

•Evil twin (D): This refers to a fraudulent Wi-Fi network mimicking a legitimate one. Since the users are on a wired network (ipconfig output checked), this is not applicable.

Troubleshooting poor performance of a newly installed access point involves multiple steps. Checking for network bottlenecks and ensuring the device firmware is up to date are crucial first steps. The document confirms:“Network bottlenecks can severely limit the performance of even the fastest wireless access points, so it’s essential to verify that no other devices are causing a slowdown. In addition, keeping firmware updated ensures optimal performance and security.”

Autonomous access points operate independently without needing to communicate with a central wireless LAN controller. This is ideal for remote deployments.

From Andrew Ramdayal’s guide:

“Autonomous access points are stand-alone devices that manage their own configurations and operations. They do not require a WLC and are ideal for small or remote office deployments.”

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.”

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

To troubleshoot all the network components and review the cable test results, you can use the following steps:

Click on each device and cable to open its information window.

Review the information and identify any problems or errors that may affect the network connectivity or performance.

Diagnose the appropriate component(s) by identifying any components with a problem and recommend a solution to correct each problem.

Fill in the remediation form using the drop-down menus provided.

Here is an example of how to fill in the remediation form for PC1:

The component with a problem is PC1.

The problem is Incorrect IP address.

The solution is Change the IP address to 192.168.1.10.

You can use the same steps to fill in the remediation form for other components.

To enter commands in each device, you can use the following steps:

Click on the device to open its terminal window.

Enter the command ipconfig /all to display the IP configuration of the device, including its IP address, subnet mask, default gateway, and DNS servers.

Enter the command ping  to test the connectivity and reachability to another device on the network by sending and receiving echo packets. Replace with the IP address of the destination device, such as 192.168.1.1 for Core Switch 1.

Enter the command tracert  to trace the route and measure the latency of packets from the device to another device on the network by sending and receiving packets with increasing TTL values. Replace with the IP address of the destination device, such as 192.168.1.1 for Core Switch 1.

Here is an example of how to enter commands in PC1:

Click on PC1 to open its terminal window.

Enter the command ipconfig /all to display the IP configuration of PC1. You should see that PC1 has an incorrect IP address of 192.168.2.10, which belongs to VLAN 2 instead of VLAN 1.

Enter the command ping 192.168.1.1 to test the connectivity to Core Switch 1. You should see that PC1 is unable to ping Core Switch 1 because they are on different subnets.

Enter the command tracert 192.168.1.1 to trace the route to Core Switch 1. You should see that PC1 is unable to reach Core Switch 1 because there is no route between them.

You can use the same steps to enter commands in other devices, such as PC3, PC4, PC5, and Server 1.

Voice VLANs rely on 802.1Q tagging to separate voice traffic from data traffic on the same physical link. This separation allows QoS policies to prioritize VoIP, reducing jitter and packet loss.

B. Jumbo frames improve throughput for large data transfers, not voice.

C. Native VLAN is the untagged VLAN, not specifically for voice.

D. Link aggregation bundles links for bandwidth/redundancy, not QoS.

References (CompTIA Network+ N10-009):

Domain: Network Infrastructure — VLANs, voice VLANs, 802.1Q tagging, QoS.

The correct answer is Load balancer because it is specifically designed to distribute incoming network traffic across multiple backend servers that provide the same application or service. According to CompTIA Network+ (N10-009) objectives under network infrastructure, load balancing improves performance, scalability, and high availability by preventing any single server from becoming overwhelmed.

A load balancer can operate at Layer 4 (transport layer, based on IP address and port) or Layer 7 (application layer, based on content such as HTTP headers or URLs). It uses various algorithms such as round-robin, least connections, or weighted distribution to efficiently allocate client requests among servers. If one server fails, the load balancer can redirect traffic to healthy servers, ensuring service continuity.

A router (Option A) forwards packets between different networks but does not distribute traffic among servers running the same application. A switch (Option B) forwards frames within a local network based on MAC addresses. A firewall (Option C) filters traffic based on security rules but does not perform traffic distribution for load-sharing purposes.

Therefore, a load balancer is the correct solution for redistributing traffic among multiple servers.

The default gateway for a network should be an IP address within the subnet, but not the broadcast address. In this case:

IP: 192.163.1.15

Subnet Mask: 255.255.255.0

This means the network range is: 192.163.1.0 - 192.163.1.255

192.163.1.255 is the broadcast address for this subnet, so it cannot be used as a gateway.

Hence, the device fails to communicate outside its subnet because it's trying to use a broadcast address as its gateway.

✅ The issue is clearly with the gateway configuration.

Understanding the Requirements

Network Address: 192.168.1.0/24

The /24 notation means a subnet mask of 255.255.255.0, providing 256 total addresses (192.168.1.0–192.168.1.255).

Usable hosts: 256 – 2 (network and broadcast) = 254.

Goal: Create 3 subnets, each with 30 hosts.

Each subnet needs enough addresses to accommodate 30 hosts, plus 2 reserved addresses (network and broadcast) per subnet.

Total addresses per subnet = 30 (hosts) + 2 (network/broadcast) = 32 addresses.

Subnetting Basics (Networking Fundamentals)

Subnet Mask: Determines how many bits are borrowed from the host portion to create subnets.

Original Mask: /24 (255.255.255.0) = 24 network bits, 8 host bits.

Formulae:

Number of subnets = 2^(number of borrowed bits).

Number of addresses per subnet = 2^(remaining host bits).

Usable hosts per subnet = 2^(remaining host bits) – 2.

We need:

At least 3 subnets.

At least 32 addresses per subnet (to fit 30 hosts + 2 reserved).

Step-by-Step Analysis

Determine Addresses Needed per Subnet:

32 addresses is a power of 2 (2^5 = 32).

This means each subnet requires 5 host bits (since 2^5 = 32 total addresses, and 32 – 2 = 30 usable hosts).

Calculate Remaining Bits:

Original network has 8 host bits (/24).

If 5 bits are left for hosts, we borrow: 8 – 5 = 3 bits for subnetting.

New Subnet Mask:

Original mask: /24 (24 network bits).

Borrow 3 bits: 24 + 3 = /27.

/27 = 255.255.255.224 (binary: 11111111.11111111.11111111.11100000).

Verify Requirements:

Number of Subnets: 2^3 = 8 subnets (meets the requirement of at least 3).

Addresses per Subnet: 2^5 = 32 addresses.

Usable Hosts per Subnet: 32 – 2 = 30 hosts (exactly meets the requirement).

Subnet Breakdown:

Increment: 256 – 224 = 32 (each subnet increments by 32 in the fourth octet).

Subnets:

192.168.1.0–192.168.1.31 (Network: .0, Broadcast: .31, Hosts: .1–.30)

192.168.1.32–192.168.1.63 (Network: .32, Broadcast: .63, Hosts: .33–.62)

192.168.1.64–192.168.1.95 (Network: .64, Broadcast: .95, Hosts: .65–.94)

(And 5 more subnets up to 192.168.1.255.)

Three subnets fit perfectly with 30 hosts each.

Evaluating the Options

A. 255.255.255.128 (/25):

Borrow 1 bit: 24 + 1 = /25.

Subnets: 2^1 = 2 (not enough, need 3).

Host bits: 7 (2^7 = 128 addresses, 126 hosts).

Why Not: Only 2 subnets, fails the requirement.

B. 255.255.255.192 (/26):

Borrow 2 bits: 24 + 2 = /26.

Subnets: 2^2 = 4 (meets 3).

Host bits: 6 (2^6 = 64 addresses, 62 hosts).

Why Not: 62 hosts exceeds 30, but it’s overkill; /27 is more efficient and still valid.

C. 255.255.255.224 (/27):

Borrow 3 bits: 24 + 3 = /27.

Subnets: 2^3 = 8 (meets 3).

Host bits: 5 (2^5 = 32 addresses, 30 hosts).

Why Yes: Perfectly fits 3 subnets with exactly 30 hosts each.

D. 255.255.255.240 (/28):

Borrow 4 bits: 24 + 4 = /28.

Subnets: 2^4 = 16 (meets 3).

Host bits: 4 (2^4 = 16 addresses, 14 hosts).

Why Not: Only 14 hosts per subnet, fails the 30-host requirement.

Why /27 (255.255.255.224) is Best

It provides exactly 30 usable hosts per subnet, avoiding waste while meeting the minimum requirement.

It allows 8 subnets, exceeding the need for 3, ensuring flexibility.

The study guide emphasizes efficient subnet design, and /27 balances host count and subnet availability.

CompTIA Network+ Context

Networking Fundamentals: Subnetting is a core skill, requiring understanding of CIDR, binary conversion, and address allocation.

Example from Study Guide: Similar problems calculate subnet masks for specific host counts, reinforcing /27 as a common solution for ~30 hosts.

A Client-to-Site VPN allows a remote user to securely connect to a company's internal network, providing access as if they were physically on-site.

The correct answer is Autonomous system path because BGP (Border Gateway Protocol) prevents routing loops by using the AS_PATH attribute. According to CompTIA Network+ (N10-009) objectives under routing protocols, BGP is a path vector protocol used to exchange routing information between autonomous systems (AS) on the internet.

When a BGP router advertises a route, it includes its autonomous system number (ASN) in the AS_PATH attribute. As the route passes through additional autonomous systems, each AS appends its own ASN to the path. If a BGP router receives a route advertisement that already contains its own ASN in the AS_PATH list, it recognizes this as a loop and rejects the route. This mechanism effectively prevents routing loops across large-scale networks such as the internet.

Option B (Peer autonomous system) refers to neighboring BGP routers but does not describe the loop prevention mechanism. Option C (Autonomous system length) relates to path selection metrics, as shorter AS_PATH lengths are generally preferred, but this is not the loop avoidance function itself. Option D (Public autonomous system) is not a loop prevention mechanism.

Therefore, BGP uses the AS_PATH attribute for loop avoidance.