Troubleshooting Wired and Wireless Network Problems( Comptia Objective 5.7)

Question 1

What are the two Networked based resource issues?

Answer 1

• Local resources issues, user can’t connect to other systems on the local LAN.
• Internet based resource issues: Users can’t have access to the internet, websites, VPN etc. Can be caused by IP related issues

Question 2

If you have no Network connectivity what steps should you take?

Answer 2

• First Check for link light on the ethernet port this will tell you if it’s connected to a switch/ router on other end.
• Next try pinging the local host at 127.0.0.1 or “ Ping localhost” to make sure the protocol stack inside your OS and network card are working and TCP/IP if functioning properly.
• Next try pinging the local IP address. Can be found by going to cmd and typing” ipconfig” this checks the local configuration, ethernet adapter and link signal
• Next try pinging something outside the system such as the default gateway( router) to confirm if we can connect out to the network
• From there you can try to ping out to the internet such as pinging googles DNS server “ Ping 8.8.8.8”

Question 3

What are the range of IP addresses assigned to APIPA link local addresses?

Answer 3

• 169.254.1.0 to 169.254.254.255
• These addresses are automatically assigned when a DHCP server is unavailable
• Uses ARP to confirm current address hasn’t been assigned to anything else.

Question 4

If you have having trouble accessing local resources( shares) on the local LAN what can this be caused by?

Answer 4

• Server may be unavailable
• Share permissions could have been modified. Printers will also have the same issues.
• Could be caused by a DNS related issue.
• If you’re having issues accessing email it can also be related to the servers being used for email or the network path used.

Question 5

If you network device says it has limited or no connectivity in the windows system tray what can be the issue and how can it be fixed?

Answer 5

• Check and see if the system was assigned an APIPA link local address. This will allow systems on the local network to communicate with each other but not out to the internet.
• If the system was assigned a DHCP IP address then you can try the different pings to help solve the issue. E.g ping local host, ping default gateway, ping local IP address, ping a website etc.

Question 6

If you are having intermittent connectivity how can this be addressed?

Answer 6

• Check the system tray and check for any internet related icons.
• A broken LAN symbol is usually caused by a loss of signal. Check for a cable problem
• Next may want to check the local NIC to make sure it’s working properly( Ping localhost)
• If Cabling and local network card is working properly we may have a problem with the switch or WAP/ Wireless router it could be cotinuiously rebooting causing loss of signal.

Question 7

Network related issues related to IP conflicts are usually caused by?

Answer 7

• DHCP server not assigning an address and then a static IP address being assigned resulting in an IP conflict.
• Typically windows and most other OS will advise if there is a duplicate IP address on the network.
• Two devices sharing the same IP address can cause intermittent network connectivity issues, sometimes it works and sometimes not. Often restarting or rebooting the NIC will restart the DHCP process and help resolve IP conflicts.

Question 8

What can slow transfer speeds commonly be caused by and how can they be addressed?

Answer 8

• Can often be caused by the router or infrastructure congestion( overloaded network or devices)
• Could be caused by a speed/ duplex incompatibility of the local interface card. Check settings to confirm if setup correctly.
• Also can be caused by a hardware related issue such as a bad cable or faulty NIC( ping localhost or replace cable)
• Can also be a sign of a Malware infection.

Question 9

Low RF wireless signal related issues can be caused by and can be fixed by?

Answer 9

• Interference( Something else is using our frequency)
• Can also be caused by the signal strength want to look at transmitting signal from the WAP, look at the transmitting antenna, and check receiving antenna on local workstation.
• Can be caused by not being the on the same channel as your WAP( Wireless access point) this is usually automatic but check any manual settings.
• Can also be caused by bounce and latency related issues due to objects in the path of the wireless signal.
• Also be related to incorrect Access point placement. . Want want to move closer to the users to help reduce any signal loss due to objects in the way.

Question 10

Wireless Interference is another common Network related issue to troubleshoot. What is it’s cause and how can it be remedied?

Answer 10

• Can often be caused by interference from items such as florescent lights, microwave ovens, cordless phones, High power sources such as generators and transformerse
• Can be caused by other tenants in the same building using the same wireless channel.
• Check signal strength using things such as Performance monitor in windows or a third party wifi analyzer.

Question 11

SSID not found is another common network related issue. How can this be remedied?

Answer 11

• Network name doesn’t appear could be caused because you are too far away from the Wireless Access point.
• Wireless access point/ router may have have disable SSID advertisement so it will never appear on the list of available WIFI connections. You can still manually connect if you know the full name and password.
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