A network administrator needs to assign IP addresses to a newly installed network. They choose 192.168.1.0 /24 as their network address and need to create three subnets with 30 hosts on each subnet. Which of the following is a valid subnet mask that will meet the requirements?
Correct Answer: C
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.
Question 167
A critical infrastructure switch is identified as end-of-support. Which of the following is the best next step to ensure security?
Correct Answer: B
Understanding End-of-Support: End-of-Support Status: When a vendor declares a device as end-of-support, it means the device will no longer receive updates, patches, or technical support. This poses a security risk as new vulnerabilities will not be addressed. Risks of Keeping an End-of-Support Device: Security Vulnerabilities: Without updates, the switch becomes susceptible to new security threats. Compliance Issues: Many regulatory frameworks require that critical infrastructure be maintained with supported and secure hardware. Best Next Step - Replacement: Decommission and Replace: The most secure approach is to replace the end-of-support switch with a new, supported model. This ensures the infrastructure remains secure and compliant with current standards. Planning and Execution: Plan for the replacement by evaluating the network's needs, selecting a suitable replacement switch, and scheduling downtime for the hardware swap. Comparison with Other Options: Apply the Latest Patches: While helpful, this does not address future vulnerabilities since no further patches will be provided. Ensure the Current Firmware Has No Issues: This is only a temporary measure and does not mitigate future risks. Isolate the Switch from the Network: Isolating the switch may disrupt network operations and is not a viable long-term solution. Reference: CompTIA Network+ study materials on network maintenance and security best practices.
Question 168
During a security audit, a consulting firm notices inconsistencies between the documentation and the actual environment. Which of the following can keep a record of who made the changes and what the changes are?
Correct Answer: B
Configuration monitoring and management tools (often part of network management systems) maintain version-controlled records of device configurations, track changes, and log who made them. This provides accountability and supports compliance audits. A . Network access control (NAC) manages endpoint access policies but does not track device config changes. C . Zero Trust is a security framework requiring strict identity verification, not a configuration tracking tool. D . Syslog collects system logs, but without a config monitoring system, it does not directly compare documentation to device state. Reference (CompTIA Network+ N10-009): Domain: Network Operations - Change management, configuration management, auditing.
Question 169
Which of the following appliances provides users with an extended footprint that allows connections from multiple devices within a designated WLAN?
Correct Answer: C
An access point (AP) provides users with an extended footprint that allows connections from multiple devices within a designated Wireless Local Area Network (WLAN). Router: Typically used to connect different networks, not specifically for extending wireless coverage. Switch: Used to connect devices within a wired network, not for providing wireless access. Access Point (AP): Extends wireless network coverage, allowing multiple wireless devices to connect to the network. Firewall: Primarily used for network security, controlling incoming and outgoing traffic based on security rules, not for providing wireless connectivity. Network Reference: CompTIA Network+ N10-007 Official Certification Guide: Explains the roles and functions of network appliances, including access points. Cisco Networking Academy: Provides training on deploying and managing wireless networks with access points. Network+ Certification All-in-One Exam Guide: Covers network devices and their roles in creating and managing networks.
Question 170
A network architect needs to create a wireless field network to provide reliable service to public safety vehicles. Which of the following types of networks is the best solution?
Correct Answer: A
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. Reference: CompTIA Network+ study materials.
