Verifying full system functionality occurs after implementing a fix. This step ensures the solution resolved the issue and that performance is back to expected levels. Comparing current throughput to baseline measurements is part of validation testing to confirm everything is within normal operational parameters.
A . Implement the solution applies the fix but does not confirm results.
C . Document findings happens at the end of troubleshooting.
D . Test the theory comes earlier, when trying to confirm the suspected cause.
Reference (CompTIA Network+ N10-009):
Domain: Network Troubleshooting - Troubleshooting methodology steps, baselines, verification testing.

See the solution configuration below in Explanation.

A Security Information and Event Management (SIEM) system collects, correlates, and analyzes logs from multiple sources in real-time, providing enhanced visibility across multivendor environments.
Breakdown of Options:
A). SNMP - SNMP is used for network device monitoring, but it lacks real-time correlation across multiple vendors.
B). SIEM - Correct answer. SIEM aggregates, analyzes, and correlates logs from multiple sources, providing real-time visibility.
C). Nmap - Nmap is a network scanning tool used for mapping hosts and detecting open ports but does not provide log correlation.
D). Syslog - Syslog collects logs but does not correlate or analyze them in real-time.
Reference:
CompTIA Network+ (N10-009) Official Study Guide - Domain 3.3: Explain network security concepts.
NIST Special Publication 800-92: Guide to Computer Security Log Management

Comprehensive and Detailed Explanation:
When anew VLAN is created, it typically exists on a different subnet. IfDHCP servers are on a different VLAN, the networkneeds an IP helper addressto forward DHCP requests correctly. Without it, clients in the new VLANwon't receive an IP address.
Breakdown of Options:
* A. Scope size- Increasing the DHCP scope would not resolve the issue if requestsaren't reaching the server.
* B. Address reservations- Reservations only assign specific addresses to devices; they do not fix DHCP communication issues.
* C. Lease time- Changing the lease timedoes not impact DHCP functionality across VLANs.
* D. IP helper-Correct answer.This forwardsDHCP requestsacross VLANs to the DHCP server.

When a network interface's indicator lights are not blinking on either the computer or the switch, it suggests a physical layer issue. Here is the detailed reasoning:
Ethernet Properly Connected: The Ethernet cable is correctly connected, eliminating issues related to a loose or faulty cable.
No Indicator Lights: The absence of blinking indicator lights on both the computer and the switch typically points to the port being administratively shut down.
Switch Port Shut Down: In networking, a switch port can be administratively shut down, disabling it from passing any traffic. This state is configured by network administrators and can be verified and changed using the command-line interface (CLI) of the switch.
Command to Check and Enable Port:
bash
Copy code
Switch> enable
Switch# configure terminal
Switch(config)# interface [interface id]
Switch(config-if)# no shutdown
The command no shutdown re-enables the interface if it was previously disabled. This will restore the link and the indicator lights should start blinking, showing activity.