Chapter 21: Network Troubleshooting Flashcards
Open Circuit
When a wire doesn’t connect from end to end.
Short
When a wire connects to another wire in the cable.
Wire Map Problem
When a wire doesn’t connect to the proper place
Crosstalk
When the electrical signal bleeds from one wire pair to another.
Multimeter
Tests voltage, resistance, and continuity
Butt Sets
Tap into a 110-block to see if a line is working
arp
Command to view and change the ARP table
route print
Command used to display and edit the routing table.
nbtstat -n
Used to check the NetBIOS name cache and their corresponding IP addresses.
netstat
Displays info on your running IP processes
netstat -r
Shows the routing table
Port Scanner
Used to look for unintentionally opened ports
Throughput Testers
Measure the data flow in a network
Nmap
A popular port scanner
Divide and Conquer
Getting a general sense of where the problem lies, then starting from that layer of the OSI model
If a device is not discovering neighboring devices it may be….
DHCP or DNS issues
Concerning link aggregation, what could cause LACP to not initiate?
Both ports set to passive
Broadcast Storm
Nonstop broadcast frames being sent onto the network.
No one can reach the rest of the network.
Routing Loop
Routers loop traffic, causing them to respond slowly or not at all.
Huge amount of traffic on the links between the routers
Split Horizon
When a router learns a route through a certain interface, it will not not communicate it out that same interface.
