Network Troubleshooting and Tools Flashcards
Which should you do during the process of identifying the problem?
Duplicate the problem
Establish a plan of action
Question users
Create a hypothesis
Duplicate the problem
Question users
During the identification of a problem, you should question users and try to duplicate the problem
Which technique is used to determine the root cause of a problem, in which you split a system into smaller subprocesses for examination?
Top-to-bottom OSI analysis
Divide and conquer analysis
Bottom-to-top OSI analysis
Divide and conquer analysis
The divide and conquer analysis technique is used to divide complex processes into small subprocesses that are easier to analyze
What is the next step in problem solving once a theory is confirmed?
Create a hypothesis
Consider multiple approaches
Establish a plan of action
Establish a plan of action
After a theory or hypothesis is confirmed, you should establish a plan of action to resolve the problem
hat is the final step in resolving a problem?
Implement a solution
Validate a theory
Document
Document
The documentation of the finding, actions, and outcomes is the final step in the resolution of a problem. It allows us to solve future problems more quickly
Which tool is used to troubleshoot wiring breaks in network cabling?
OTDR
Tone generator
TDR
TDR
A time domain reflectometer is a tool that sends electronic pulses of energy down a wire and reads the time their reflection comes back. A calculation is made to determine the length of the cable
You need to find a network cable that is not labeled on a wiring panel; which tool should you use to identify the cable?
Cable tester
Tone generator
TDR
Tone generator
A tone generator is used in conjunction with a tracing probe to identify network cables. It operates by injecting a warbling tone into the cable so that the tracing probe can amplify the signal audibly
You are working alone and want to test a fiber-optic cable. Which tool will help you test the fiber-optic cable quickly?
TDR
Light meter
Loopback adapter
Loopback adapter
Although you could use a light meter to test the fiber-optic cable, you would need to move the source over to the other fiber strand. A loopback adapter will allow you to test the cable with one test of both strands
Which software tool will allow you check if a web application running on a server is online?
nslookup
tracert/traceroute
Port scanner
Port scanner
A port scanner will allow you to check if an application is accepting connections. The port will return an open status, and most port scanners will check for an HTTP response. The ping utility will only check if the server is online
You believe there is problem upstream of your Internet connection and want to gather information to provide the ISP. Which tool will you use to gather statistics?
tracert/traceroute
pathping
nslookup
pathping
The pathping tool will perform a traceroute to the destination address. It will then check each hop with a number of ICMP packets and return statistics on each hop
Which tool allows examination at the packet level for traffic from an application?
Protocol analyzer
dig
Spectrum analyzer
Protocol analyzer
A protocol analyzer will allow us to inspect packet levels of traffic that is captured from an application
You need to check the configured MTU on the interface of a Linux host; which command should you use?
ipconfig
ifconfig
mtuconfig
ifconfig
The ifconfig command will allow you to inspect the MTU on the interface of a Linux host. It will also allow you to change the MTU temporarily
You need to check the port an application is listening on; which command should you use to view the information?
portqry
ifconfig
netstat
netstat
The netstat command will allow you to see layer 4 binding between applications and the TCP/UDP ports. On Windows, the netstat -ab command will display listening ports. On Linux/Unix, the netstat -ap command will perform the same function
You need to analyze whether an application is responding to a client request; which command will allow you to capture the traffic?
tcpdump
nmap
portqry
tcpdump
The tcpdump command will allow packet capture of an interface. When run on the server the application is responding on, tcpdump can capture the response of the application for further analysis
Which command will allow you to clear the cached MAC addresses on a host?
arp -g *
ipconfig /flushdns
arp -d *
arp -d *
The arp command allows you to manipulate the MAC address cache of a host. When you issue the arp -d * command, you will clear all MAC address entries in the ARP cache
Which describes what happens to a wireless signal as it moves further away from the source?
Increased latency
Increased jitter
Increased attenuation
Increased attenuation
The attenuation of the signal increases as the signal moves further away from the source. Attenuation is the gradual absorption of a signal’s energy in the air
You believe there is a break in a fiber-optic cable that spans 5 miles; which tool will help you determine where the cable break cable is?
TDR
OTDR
Cable tester
OTDR
An optical time-domain reflectometer (OTDR) sends a pulse of light down the fiber-optic cable and measures the time and reflection strength. This measurement will determine where a break occurs in the fiber-optic cable
Which Nmap scan will send an URG, PSH, and FIN flag to trick the operating system to respond with an RST?
Xmas-tree scan
Fin scan
Null scan
Xmas-tree scan
The Xmas-tree scan will send the URG, PSH, and FIN flags in the TCP header to trick the operating system into sending back an RST for closed ports
As routers, switches, and NAT processes are added to a routed switch path, what happens?
Latency increases
Jitter increases
Latency decreases
Latency increases
Latency is the measurement of delay between the source and destination. As components such as switches, routers, and NAT processes are added, latency is increased because of the lookups and forwarding
Which term describes the phenomenon of a wireless signal changing in frequency as it passes through different materials?
Reflection
Attenuation
Refraction
Refraction
As a wireless signal passes through different materials, the signal will slow down and change in frequency. This phenomenon is called refraction, similar to a prism and light
You find that a workstation has no connectivity to the network. When you use ipconfig, the IP address reports as 169.254.34.22 with a subnet mask of 255.255.0.0. What is the possible problem?
The subnet mask is incorrect.
The IP address is on the wrong subnet.
The original IP address has expired.
The original IP address has expired.
The 169.254.x.x prefix is an Automatic Private IP Addressing (APIPA) IP address, also called a link local address. The presence of this address means that either the original DHCP address has expired or the DHCP server is unavailable
You believe that packets are being routed via the wrong gateway; which tool will allow you to verify the route a packet takes to the destination IP address?
route print
tracert
ipconfig
tracert
The tracert command will allow you to see the path an IP packet takes to the destination. The Linux/Unix command is traceroute
You are diagnosing a wireless issue and you believe that the problem is related to RF noise. Which measurement should you focus on to prove your theory?
RSSI
SNR
dB strength
SNR
Wireless access point (WAP) diagnostics and spectrum analyzers will display RSSI and SNR. The signal-to-noise ratio is the separation of signal to floor noise measured in decibels (dB). The SNR will prove the theory of excess RF noise compared to the originating signal
What is the outcome if you have a speed mismatch on a network connection?
High collision rate
High error rate
No link status
No link status
If there is a speed mismatch between the two connection devices, you will have no link status, because the carrier signal is different
You have a high error rate on an interface and believe that crosstalk is to blame. What should be checked to prove your theory?
Network cable specifications
Duplex
Speed
Network cable specifications
Crosstalk happens when the electrical signals on one wire induces erroneous signals on another wire. The correct category cable specifications are defined by the Telecommunications Industry Association (TIA)
Which command is used to verify the configuration of a host-based firewall on a Linux host?
nmap
iptables
ifconfig
iptables
The iptables command allows configuration and inspection of the host-based firewall in many Linux distributions
