5.5 Use tool/protocol for network issues

Question 1

Protocol Analyzer (Wireshark)

Answer 1

A tool used to capture and decode deep packet information to see exactly what is happening in a communication.

Question 2

ping

Answer 2

Uses ICMP Echo Requests to test basic connectivity between two IP addresses (Layer 3).

Question 3

traceroute / tracert

Answer 3

Shows the path (hops) a packet takes to a destination; used to find exactly where a connection is failing.

Question 4

nslookup / dig

Answer 4

Command-line tools used to test DNS name resolution and query DNS records.

Question 5

tcpdump

Answer 5

A command-line packet sniffer (Linux/Unix) used to capture or filter network traffic.

Question 6

netstat

Answer 6

Displays all active network connections (inbound/outbound), routing tables, and interface statistics.

Question 7

ipconfig / ifconfig / ip

Answer 7

Displays the local IP address, subnet mask, and default gateway for the host machine.

Question 8

arp (Command)

Answer 8

Displays and modifies the local ARP cache; used to view MAC-to-IP address mappings.

Question 9

Nmap

Answer 9

A powerful network scanner used for network discovery, port scanning, and vulnerability assessments.

Question 10

CDP / LLDP

Answer 10

Layer 2 discovery protocols (Cisco-proprietary vs. Standard) used to see information about directly connected neighboring devices.

Question 11

Toner and Probe (Fox and Hound)

Answer 11

A hardware tool used to locate a specific cable in a cluttered patch panel by sending an audible tone.

Question 12

Cable Tester

Answer 12

A hardware tool used to check for physical continuity, shorts, and crossed wires in a copper cable.

Question 13

Network Tap (TAP)

Answer 13

A hardware device that provides a way to access data flowing across a computer network for monitoring/sniffing.

Question 14

Wi-Fi Analyzer

Answer 14

A tool (hardware or app) used to view signal strength (RSSI), channel interference, and AP locations.

Question 15

Visual Fault Locator (VFL)

Answer 15

A fiber-optic ‘flashlight’ used to find breaks, leaks, or bad splices in a fiber cable.

Question 16

show mac-address-table

Answer 16

Switch command to see which MAC addresses are learned on which physical ports.

Question 17

show interface

Answer 17

Command used to check for CRC errors, collisions, and the up/down status of a physical port.

Question 18

show config (running-config)

Answer 18

Displays the current active configuration stored in a device’s RAM.

Question 19

show power (inline)

Answer 19

Command used on PoE switches to see how much wattage is being used by connected devices.