Lesson 15 Troubleshooting Network Issues Flashcards
What are the troubleshooting steps
Identify the problem
Establish probable cause
Test theory
Establish a plan of action
Implement the solution
Verify functionality
Document
What is ipconfig or ifconfig used for
to determine if host is configured for static or dynamic IP addressing
If host has valid IP address
What is ping used for
Connectivity troubleshooting
What is the ping command for IPv^
ping -6 (Windows)
ping6 (Linux)
What is the loopback address
127.0.0.1
What can you ping
Loopback address
specific device
host name
own IP address
default gateway
remote host
What are the ping responses
Reply from
Destination Network / Host Unreachable
Unknown Host
Request timed out
Hardware Error
What is traceroute and tracert used for
Traces communication until it gets an error
Tells where the connection failed
Which OS uses traceroute
LInux
Which OS uses tracecert
Windows
What is the ARP utility is used for
Add or delete ARP cache entries
Locating a node’s hardware address
Entries are permanent until deleted or device is powered down
What is the ARP cache used for
Maintaining a correlation between MAC and IP addresses
How do you reduce the number of ARP requests
Have addresses resolves in the cache for a short period of time
Flush the ARP cache periodically
If you can’t communicate between two host you can use arp utility to
compare the arp caches in each device to make sure that they are correct
What is NBTSTAT used for
Windows based
To view and manage NetBIOS over TCP/IP
Displays NETBIOS name tables for local and remote devices
You can verify connection establishment and refresh the NetBIOS name cache as well as names on the WINS server
What is NETSTAT used for
Shows status of each active network connection
NETSTAT shows statistics for
TCP and UDP
Local protocols
Local address
Foreign address
TCP connection state
What else can NETSTAT be used for
To find out if a TCP/IP program is listening on the expected port
Check connection status
Check network adapter error counts
Displays routing tables
What is nslookup used for
To test the domain name servers
It has two modes interactive (lists all) an non-interactive (list specific devices)
What is the DIG unix/Linux command
Used to display name server information. Maybe easier to use than nslookup
Why is WLAN survey software used
Used to analyze WLAN performance before and after implementation
SNIPS is used with which OS
UNIX
What is SNIPS
Network monitoring software
Reports status of services running on the network
Can set alarms as info, warning, error and crtical
What is a loopback interface used for
To test IP software without any potential issues from broken or corrupted drivers or hardware
What is the IPv4 loopback address
127.0.0.1
What is the IPv6 loopback address
::1
What do speed test measure
speed and latency
What is a looking glass site
Web server that allows user to get a look at routing and network behavior as it originates from the remote network.
Accesses a remote router and performs commands to of the IP and Border Gateway Protocol route tables
Used to verify routing between providers and verifying routes
This device attaches media connectors to the ends of cables
Crimper (wire or cable)
Used to stripper insulation from wires
Strippers
Used to connect cables to patch panels
Punch down tool
Used to see if current is passing between circuits
Circuit tester
Used to test voltage and resistance
Multimeter
or
Voltmeter (can be used with VERs)
Used to verify that a signal is transmitted by a cable
Cable tester
Used to conduct cable and validity testing. It looks for shorts, crosstalk, it tests for cable type, determines if a cable is a straight through or crossover cable
Cable Certifier
What type of cable is used to connect unlike devices
crossover cable
allows you to connect devices without a hub or switch
What type of cable is used to connect like devices
pass through
Which tool measures the electrical pulse on a cable and the amount of reflected signal
TDR
Which type of tool is used with fiber testing
OTDR
What else can OTDRs measure
Cable Length
Locations of faulty splices, breaks, connectors, and bends
Cable attenuation
What device can send an electrical signal through a UTP wire
Tone Generator
Tone Generators are used to
Trace wires for continuity and faults
What ensures environmental conditions
Enviro monitors
Used by linemen for troubleshooting phone lines
Butt Set
Link Indicators tell
Signal reception
Activity indicators tell
Tells received or sent data packets
Network Analyzer
Protocol analyzer or packet sniffer
Can be used to defect network intrusions
What is a demarc
Where private wire ends and provider wire begins
WiFi testers check for
Detects devices and interference
Light meters doe what
Detect the signal strength of light down a fiber cable
Common physical issues with networks
Crosstalk
Near end cross talk
Far end cross talk
Attenuation
Collisions
Shorts
Open Impedance mismatch
Interference
SFP/GBIC
Pg 616
What are some network logical issues
Port speed
Port duplex mismatch
VLAN assignment
Interface misconfiguration
Interface errors
Wrong Default gateway
Misconfigured DHCP
Misconfigured DNS
Duplicate IPs
Power failure
IP routes
NIC teaming misconfiguration
Unpatched system
Loss of connectivity
Split horizon
Router configurations
Premise wiring
Security policy
Satellite issues
PG 619
Common route and switching issues
Switching loop
Routing loop
Route problems
Proxy ARP
Broadcast storms
Port configurations
VLAN assignment
Mismatched MTU
Pg 623
Common wireless issues
Interference
Incorrect encryption type
Overlapping channels
Incorrect frequency
SSID mismatch
Standard mismatch
Signal strength loss
Bounce
Antenna placement
AP configuration
Incompatibilities
Incorrect channel
Latency
AP placement
Bandwidth saturation
Open network
Power levels
Rogue Access points
Wrong antenna
Pg 624
Describe a troubleshooting model
Step by Step process in the correction of a problem
Net + Troubleshooting model has how many steps
7
Which command lines will allow you to view the hosts IP configurations
IPconfig or IFconfig
Pinging by IP address instead of hostname will reveal what
name resolution issues
Tracert command for IPV4 and IPV6
Tracert
Tracert -6
Traceroute command for IPV4 and IPV6
Traceroute
Tracerout6
To reduce the number of ARP requests a client does what
The client has all the addresses resolved in the cache for a short period of time
Is the ARP cache finite
yes
How do you free up space in the ARP cache
Periodically flush it of all entries
ARP is best used for diagnosing what
Duplicate IP address and finding out where communications failed
What is the most common ARP command line entry
arp -a
Name the different ARP command line entry options
inet_addr
eth_addr
if_addr
- a
- g
- N if_addr
- d
- s inet_addr eth_addr
Page 590
If the ping command is blocked by a firewall, what can you do
Use ARP to find the host by MAC address and bypass the IP address resolution
Name the different command lines for maintencance
Ping
ARP
NBTstat
NETSTat
Name the different NBTstat command line entry options
See pg 591
Which command shows the status of network connections for TCP, UDP inclding protocol, local addresses, foreign addresses, and TCP connection state
NETSTAT
Name the different NETSTAT command line entry options
See pg 592
Which command line entry display the socket states
NETSTAT
Does the loopback address use hardware
no
Types of cable tester and certifiers
Certification tester
Qualification tester
LAN tester
Network cable certifier
Hardware loopback plug is used for testing what
a machine’s NIC
What device emits an audible tone when it detects an audible signal
Tone Locator
What are the types of LED indicators
Activity
Link
Speed
Dual color
What is a smart jack
Jack that serves as a demarc between the user and the provider.
Can perform looping tests
A spectrum analyzer compares what
Signal strength against frequency
