Chapter 21: Network Troubleshooting

Question 1

Open Circuit

Answer 1

When a wire doesn’t connect from end to end.

Question 2

Short

Answer 2

When a wire connects to another wire in the cable.

Question 3

Wire Map Problem

Answer 3

When a wire doesn’t connect to the proper place

Question 4

Crosstalk

Answer 4

When the electrical signal bleeds from one wire pair to another.

Question 5

Multimeter

Answer 5

Tests voltage, resistance, and continuity

Question 6

Butt Sets

Answer 6

Tap into a 110-block to see if a line is working

Question 7

arp

Answer 7

Command to view and change the ARP table

Question 8

route print

Answer 8

Command used to display and edit the routing table.

Question 9

nbtstat -n

Answer 9

Used to check the NetBIOS name cache and their corresponding IP addresses.

Question 10

netstat

Answer 10

Displays info on your running IP processes

Question 11

netstat -r

Answer 11

Shows the routing table

Question 12

Port Scanner

Answer 12

Used to look for unintentionally opened ports

Question 13

Throughput Testers

Answer 13

Measure the data flow in a network

Question 14

Nmap

Answer 14

A popular port scanner

Question 15

Divide and Conquer

Answer 15

Getting a general sense of where the problem lies, then starting from that layer of the OSI model

Question 16

If a device is not discovering neighboring devices it may be….

Answer 16

DHCP or DNS issues

Question 17

Concerning link aggregation, what could cause LACP to not initiate?

Answer 17

Both ports set to passive

Question 18

Broadcast Storm

Answer 18

Nonstop broadcast frames being sent onto the network.

No one can reach the rest of the network.

Question 19

Routing Loop

Answer 19

Routers loop traffic, causing them to respond slowly or not at all.
Huge amount of traffic on the links between the routers

Question 20

Split Horizon

Answer 20

When a router learns a route through a certain interface, it will not not communicate it out that same interface.