CompTIA N10-009 - CompTIA Network+ Certification Exam

The server’s subnet mask is 255.255.255.224 (/27), which covers IPs from 192.168.100.224 to 192.168.100.255. However, the router only recognizes 192.168.100.0/24, indicating a mismatch between the server’s subnet and the router's network.

Correct mask for the /24 network is 255.255.255.0, allowing 256 IPs from 192.168.100.0 to 192.168.100.255.

This mismatch would result in routing issues, especially with the gateway outside of the subnet range.

📘 Reference:

CompTIA Network+ N10-009 Official Objectives: 5.2 – Given a scenario, troubleshoot common wired connectivity issues.

Link Layer Discovery Protocol (LLDP) is a network protocol used for discovering devices and their capabilities on a local area network, primarily at the data link layer (Layer 2). It helps in identifying the connected switch and the specific port to which a device is connected. When troubleshooting a VoIP handset connection, the technician can use LLDP to determine the exact switch and port where the handset is connected. This protocol is widely used in network management to facilitate the discovery of network topology and simplify troubleshooting.

Other options such as IKE (Internet Key Exchange), VLAN (Virtual LAN), and netstat (network statistics) are not suitable for identifying the switch and port information. IKE is used in setting up secure IPsec connections, VLAN is used for segmenting networks, and netstat provides information about active connections and listening ports on a host but not for discovering switch port details.

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.

802.1x is a network access control protocol that provides an authentication mechanism to devices trying to connect to a LAN or WLAN. This ensures that only authorized devices can access the network, making it ideal for mitigating the risk of unknown devices connecting to the network, especially in accessible areas.

802.1x Authentication: Requires devices to authenticate using credentials (e.g., username and password, certificates) before gaining network access.

Access Control: Prevents unauthorized devices from connecting to the network, enhancing security in public or semi-public areas.

Implementation: Typically used in conjunction with a RADIUS server to manage authentication requests.

Network References:

CompTIA Network+ N10-007 Official Certification Guide: Covers 802.1x and its role in network security.

Cisco Networking Academy: Provides training on implementing 802.1x for secure network access control.

Network+ Certification All-in-One Exam Guide: Explains the benefits and configuration of 802.1x authentication in securing network access.

IPv4 addresses are divided into classes:

Class A: Supports 16,777,214 hosts (large enterprises).

Class B: Supports 65,534 hosts (medium to large networks).

Class C: Supports 254 hosts (small to medium networks).

Class D: Used for multicast, not for assigning IPs to hosts.

Step-by-step Calculation:

The network will have 150 users initially, with a projected growth of 10 users, totaling 160 users.

Each user has two devices, so 160 × 2 = 320 IP addresses needed.

A Class C subnet has 254 usable IPs by default, which is not sufficient.

A Class B subnet can support thousands of hosts, making it the most appropriate option.

Incorrect Options:

A. Class D: Reserved for multicast, not for host assignments.

C. Class A: Overkill for a network of this size.

D. Class C: Cannot support 320 hosts without subnetting, making Class B the best choice.

Understanding Link Aggregation:

Definition: Link aggregation combines multiple network connections into a single logical link to increase bandwidth and provide redundancy.

Usage in High-Bandwidth Scenarios:

Combining Links: By aggregating multiple 1Gbps connections, the facility can utilize the full 2.5Gbps bandwidth provided by the ISP.

Benefits: Enhanced throughput, load balancing, and redundancy, ensuring better utilization of available bandwidth.

Comparison with Other Options:

802.1Q Tagging: Used for VLAN tagging, which does not affect the physical bandwidth utilization.

Network Address Translation (NAT): Used for IP address translation, not related to link speed or bandwidth aggregation.

Port Duplex: Refers to the mode of communication (full or half duplex) on a port, not the aggregation of bandwidth.

Implementation:

Configure link aggregation (often referred to as LACP - Link Aggregation Control Protocol) on network devices to combine multiple physical links into one logical link.

Definition of Heat Maps:

A heat map is a graphical representation of data where individual values are represented by colors. In the context of wireless networking, a heat map shows the wireless signal strength in different areas of a building.

Purpose of a Heat Map:

Heat maps are used to illustrate the effectiveness of wireless networking coverage, identify dead zones, and optimize the placement of access points (APs) to ensure adequate coverage and performance.

Comparison with Other Options:

Logical Diagram: Represents the logical connections and relationships within the network.

Layer 3 Network Diagram: Focuses on the routing and IP addressing within the network.

Service-Level Agreement (SLA): A contract that specifies the expected service levels between a service provider and a customer.

Creation and Use:

Heat maps are created using specialized software or tools that measure wireless signal strength throughout the building. The data collected is then used to generate a visual map, guiding network administrators in optimizing wireless coverage.

Quality of Service (QoS) is crucial for real-time services like video conferencing. It prioritizes voice and video packets over less critical traffic (like file downloads), reducing latency, jitter, and packet loss.

B. Network signal may apply to wireless, but it's not specific to video issues.

C. Time to live (TTL) affects packet lifespan, not performance or quality.

D. Load balancing manages traffic across multiple paths but doesn’t prioritize real-time traffic like QoS does.

📘 Reference:

CompTIA Network+ N10-009 Official Objectives: 3.6 – Explain the characteristics of network topologies and types.

OSPF (Open Shortest Path First) is a link-state routing protocol that uses the Dijkstra algorithm, also known as the shortest path first (SPF) algorithm, to determine the most efficient routes.

From Andrew Ramdayal’s guide:

“OSPF is a link-state routing protocol that provides fast, efficient path selection using the shortest path first (SPF) algorithm.”

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.