CompTIA Updated N10-009 Exam Questions and Answers by elian

The troubleshooting methodology requires following a logical sequence. In this case, the engineer has already identified the problem (firewall blocking traffic) and confirmed it with evidence (packet captures). The next appropriate step is to create a plan of action that outlines how to resolve the issue and considers potential effects.

A. Implementing the solution is premature without planning.

C. Establishing a theory was already completed during problem isolation.

D. Documentation occurs after resolution.

By carefully planning, the engineer ensures that corrective action won’t cause additional outages or security issues, especially given the scale of the incident (3,000 users).

References (CompTIA Network+ N10-009):

Domain: Network Troubleshooting — Troubleshooting methodology, plan of action.

MIBs (Management Information Bases) define the variables and objects that SNMP can query on a device. If the monitoring server authenticates but cannot interpret the data, it likely lacks the correct MIB for that vendor or model. Importing the proper MIB allows the monitoring server to correctly display device status and metrics.

A. Using a public community string is insecure and not related to missing MIBs.

C. Switchport analyzer (SPAN) captures traffic for packet analysis, not SNMP monitoring.

D. SNMPv3 privacy adds encryption but doesn’t fix missing MIB interpretation.

References (CompTIA Network+ N10-009):

Domain: Network Operations — SNMP, MIBs, network monitoring systems.

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.