Free CompTIA N10-009 Practice Exam with Questions & Answers | Set: 9

For 45 hosts, the minimum subnet size must allow at least 46 usable addresses (1 each for network and broadcast addresses).

A /26 subnet provides 64 addresses, 62 usable — suitable.

A /27 subnet gives only 30 usable — insufficient.

A /25 offers 126 usable — more than needed.

A /28 provides just 14 — too small.

So, the most efficient subnet with minimal wastage is /26.

From Andrew Ramdayal’s guide:

“When designing subnets, always choose the smallest subnet mask that still accommodates all hosts. A /26 provides 62 usable host addresses, suitable for networks with about 50 hosts.”

Introduction to OSI Model:

The OSI model is a conceptual framework used to understand network interactions in seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

Application Layer:

The application layer (Layer 7) is the topmost layer in the OSI model. It provides network services directly to end-user applications. This layer facilitates communication between software applications and lower layers of the network protocol stack.

Reliance on Other Layers:

The application layer relies on the transport layer (Layer 4) for data transfer across the network. The transport layer ensures reliable data delivery through protocols like TCP and UDP.

The network layer (Layer 3) is responsible for routing packets to their destination.

The data link layer (Layer 2) handles node-to-node data transfer and error detection.

The physical layer (Layer 1) deals with the physical connection between devices.

Explanation of the Options:

A. It relies upon other layers for packet delivery: This is correct. The application layer depends on the lower layers (transport, network, data link, and physical) for the actual delivery of data packets.

B. It checks independently for packet loss: This is incorrect. Packet loss detection is typically handled by the transport layer (e.g., TCP).

C. It encrypts data in transit: This is incorrect. Encryption is typically handled by the presentation layer or at the transport layer (e.g., TLS/SSL).

D. It performs address translation: This is incorrect. Address translation is performed by the network layer (e.g., NAT).

Conclusion:

The application layer’s primary role is to interface with the end-user applications and ensure that data is correctly presented to the user. It relies on the underlying layers to manage the actual data transport and delivery processes.

A mesh network is the best solution for providing reliable wireless service to public safety vehicles. In a mesh network, each node (vehicle) can connect to multiple other nodes, providing multiple paths for data to travel. This enhances reliability and redundancy, ensuring continuous connectivity even if one or more nodes fail. Mesh networks are highly resilient and are well-suited for dynamic and mobile environments such as public safety operations.References: CompTIA Network+ study materials.

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.

A load balancer is designed to distribute user requests across multiple servers to ensure high availability and performance.

Breakdown of Options:

A. Router – Directs traffic between networks, not between web servers.

B. Switch – Works at Layer 2, does not distribute web traffic.

C. Firewall – Secures network traffic, but does not distribute load.

D. Load balancer – ✅ Correct answer. Optimizes web traffic distribution across multiple servers.

For a web server that requires all connections to be encrypted, port 80 (HTTP) should be disabled. Port 80 is used for unencrypted web traffic, whereas port 443 is used for HTTPS, which provides encrypted communication.

Port 80 (HTTP): This port is used for unsecured web traffic. Disabling this port ensures that all web traffic must use HTTPS, which encrypts the data in transit.

Port 443 (HTTPS): This port is used for secure web traffic via SSL/TLS encryption. Keeping this port open ensures that secure connections can be made to the web server.

Other Ports:

Port 22: Used for SSH, providing secure remote access and file transfers.

Port 587: Used for secure email submission (SMTP) with encryption.

Network References:

CompTIA Network+ N10-007 Official Certification Guide: Discusses the roles and security implications of various ports and protocols.

Cisco Networking Academy: Provides training on secure web server configuration and port management.

Network+ Certification All-in-One Exam Guide: Covers port security and best practices for securing web servers.

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

Network Functions Virtualization (NFV): NFV is a technology that virtualizes network services like routing, firewalls, and load balancers. It allows these services to run on virtual machines rather than requiring dedicated hardware. This is ideal for remote branch locations where deploying physical devices is costly and complex.

VRF (B): Virtual Routing and Forwarding is used for segmenting routing tables but does not virtualize services.

VLAN (C): Virtual Local Area Networks help segregate broadcast domains but are unrelated to virtualizing network functions.

VPC (D): Virtual Private Cloud is used for cloud computing but does not pertain to virtualizing network services.

An on-path attack (formerly known as a man-in-the-middle (MITM) attack) involves intercepting and potentially altering communications between two parties without their knowledge. This can be done via techniques like ARP poisoning, rogue access points, or SSL stripping.

Breakdown of Options:

A. Self-signed certificate – These are untrusted SSL certificates but do not intercept traffic.

B. VLAN hopping – VLAN hopping exploits VLAN misconfigurations but does not necessarily intercept communications.

C. On-path attack – Correct answer. This intercepts and modifies traffic between two endpoints.

D. Phishing – Phishing tricks users into revealing credentials rather than intercepting network traffic.