Q9: Intro to Troubleshooting Flashcards
You have just been hired on as a member of the network administration team and are responding to an alarm for multiple network interfaces down on the Core Layer 3 switch in the network. You have verified that services are definitely impacted and have begun troubleshooting. After several minutes, you are unable to isolate the problem. What is your next step?
A. Try the CompTIA troubleshooting methodology
B. Reload the switch
C. Escalate
D. Use the Bottom-Up approach and start verifying layer 1 and then work your way up the stack
C) Escalate
Explanation: There are a couple hints here that point toward the correct answer. First, you have just been hired (translation, you don’t know the network very well). Second, multiple interfaces on the Core layer 3 switch is an extremely serious if not catastrophic situation and needs to be dealt with immediately. Escalating the problem to the next level is a legitmate way of dealing with a situation like this, Sometimes it is a matter of swallowing pride when you are forced to admit when you don’t know and someone else who is more experienced needs to figure it out. But, as a network technician, your allegiance is to the network and the users/applications that it supports.
Known as the OSI model networking layers, these layers are most commonly scrutinized during network troubleshooting.
A. Layer 1, Layer 2, Layer 3
B. Layer 3, Layer 4
C. Layer 1, Layer 2, Layer 3, Layer 4
D. Layer 2, Layer 3, Layer 4
C) Layer 1, Layer 2, Layer 3, Layer 4
Explanation: A network administrator will commonly troubleshoot problems from layer 1 through layer 4 which is why they are called the OSI model networking layers- even though we all know that the network layer is the OSI model is layer 3.
Describe the difference between the ICMP troubleshooting tools” ping” and “traceroute”
Explanation: Ping and traceroute are btoh ICMP utilities used to test in a network. Ping is used to verify layer 3 connectivity from end to end. Traceroute is used to identify the hops in the path to the destination as well as verifying the destination is reachable.
What is a very common tool you can use to verify if certain layer 4 ports are open on another device?
A. Ping
B. telnet
C. traceroute
D. port analyzer
B) telnet
Explanation: The common use for telnet is as a protocol for remote access. Using the command “ telnet x.x.x.x” will attempt to open a vty session with the device at x.x.x.x. The default port used by telnet is 23. You can change the port that it uses and when you do, you are basically knocking on the door of that port.
For example, issue the command: Router# telnet 192.168.2.1 80
This will test if port 80 is open on the target device at 192.168.2.1 ( you can also use this command to target a server.)
If the port is open, then you will see = “ trying 192.168.2.1…Open”
If the port is not open , then you will see “%Connecntion refused by remote host”
You are unable to reach the website www.cisco.com using your web browser. How can you test if DNS is resolving the url?
A. ping the DNS server
B. clear your web cache
C. ping www.cisco.com
D. browse to the ip address of the web server
D) browse to the ip address of the web server
Explanation: DNS translates the url name into an ip address. If DNS is not working, then try putting the ip address in your web browser instead. If DNS is at fault, then you should be able to access the website via the ip address. If you cannot get there via the ip address either, then it is not a DNS issue.
