The correct answer is VLSM (Variable Length Subnet Masking). According to the CompTIA Network+ N10-
009 objectives, VLSM allows a network administrator to create subnets of different sizes within the same network, making it ideal for environments where subnet host requirements vary.
In this scenario, the technician must support multiple subnet sizes-60 hosts, 15 hosts, and seven hosts- within a single Class C network. Using a single subnet mask for all eight subnets would either waste a large number of IP addresses or fail to meet host requirements. VLSM solves this problem by allowing each subnet to be assigned a custom subnet mask that closely matches its host needs, maximizing address efficiency.
CIDR enables classless addressing and route aggregation but does not, by itself, describe creating multiple subnet sizes within a single address block. APIPA is a self-assigned addressing mechanism used when DHCP fails and has no relevance to subnet design. RFC 1918 defines private IP address ranges but does not address subnetting strategies.
The Network+ objectives emphasize VLSM as a best practice for efficient IP address management, especially in enterprise environments where conserving address space and meeting diverse departmental requirements are critical. In this case, VLSM is the only solution capable of meeting all stated constraints.

nmap (Network Mapper) is the best tool in this scenario. It can scan the 192.168.1.0/24 subnet to discover live hosts, open ports (like Telnet on port 23), and device types. It's ideal for mapping and auditing the network.
A). dig is a DNS lookup tool; not useful for identifying hosts on a subnet.
C). tracert shows the path packets take to a destination, not for host discovery.
D). telnet is the protocol being used, not a tool for scanning or identifying devices.
# Reference:
CompTIA Network+ N10-009 Official Objectives: 5.1 - Given a scenario, use the appropriate network troubleshooting tools.

The issue is that more students have arrived on campus, meaning the available IP addresses are exhausted. To fix this, the administrator should increase the DHCP scope size to allow more devices to obtain IP addresses.
Breakdown of Options:
A). Enable IP helper - IP helper is used to forward DHCP requests across different subnets. However, the problem here is that the DHCP scope is full, not that requests are not reaching the server.
B). Change the subnet mask - The subnet mask determines the number of available hosts, but changing it without increasing the IP pool does not help.
C). Increase the scope size - Correct answer. Expanding the DHCP scope provides more IP addresses for assignment.
D). Add address exclusions - Exclusions reserve IP addresses, which would further reduce available addresses instead of solving the issue.
Reference:
CompTIA Network+ (N10-009) Official Study Guide - Domain 2.4: Compare and contrast IP addressing schemes.
RFC 2131: Dynamic Host Configuration Protocol (DHCP)

Tailgatingis a physical security breach where someone follows an authorized person into a restricted area without proper credentials. Once inside, the attacker can install rogue devices like unauthorized APs.
* A. Evil twinis a wireless attack where an attacker sets up a fake AP.
* B. Honeytrapis used to attract attackers for analysis.
* C. Wardrivinginvolves scanning for unsecured Wi-Fi networks while driving, not physical intrusion.
#Reference:
CompTIA Network+ N10-009 Official Objectives: 4.2 - Identify common security threats and vulnerabilities.

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.