5.7 Given a scenario, troubleshoot common wired and wireless network problems Flashcards

1
Q

____ is a state when a device is connected to the network, but can’t reach outside of the local network. Even some local resources may be not reachable.

A

Limited connectivity

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2
Q

Limited connectivity denotes what?

A

Inability for a device to connect outside of its network.

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3
Q

What are some possible causes of network issues in general?

A
Wireless interference/low signal
OS misconfiguration
Hardware misconfiguration
Cabling issues
Bottlenecking
IP conflicts
server down
permissions
incorrect password
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4
Q

If you’re connected to a wired network and you have no connectivity, make sure the cable is connected. And then look for a ___.

A

link light

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5
Q

What is a link light?

A

This will tell you that you’re connected to a switch that is on the other end of that cable.

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6
Q

How can you check if your protocol stack is working?

A

Ping the loopback interface by typing the following into cmd:

ping 127.0.0.1

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7
Q

What is a loopback interface?

A

A loopback interface is a virtual interface that is always up and reachable as long as at least one of the IP interfaces on the switch is operational. Pinging it tell you the protocol stack that’s in your operating system is working properly.

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8
Q

What is the protocol stack? What does it mean for network troubleshooting?

A

A protocol stack is a set of network protocol layers that work together. An issue with it could be a cause of limited connectivity.

(packets frames bits)

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9
Q

The next logical step after pinging the loopback address when troubleshooting No connectivity is to then ___.

A

ping your local IP address

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10
Q

How do you ping your local IP address on windows?

A

‘ipconfig’ into cmd to find your local IP address

Then ping that address

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11
Q

Why would you want to ping your local IP address?

A

It allows you to check the local configuration, the link signal, and the network adapter.

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12
Q

After pinging the local IP address to troubleshoot connectivity, what is another command you could you try?

A

Pinging the default gateway.

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13
Q

How do you ping the default gateway?

A

‘ipconfig’ into cmd to find the default gateway and ping it

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14
Q

Why would you want to ping the default gateway?

A

It allows you to check whether or not you’re able to communicate across the local network.

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15
Q

After pinging your default gateway and determine that you are able to communicate across the network, what should you attempt?

A

Try pinging something outside the local network on the other side of the router, such as the internet.
(ei. google DNS 8.8.8.8)

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16
Q

If you have not configured a static IP address on your computer and you turn on your computer and it’s not able to find a DHCP server, then it will automatically assign itself…

A

an APIPA address.

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17
Q

What is an APIPA address?

A

It is an IP address that is assigned automatically if no device responds to an ARP when a DHCP server is unavailable.

They always start with 169.254.

18
Q

___ enables computers to automatically self-configure an IP address and subnet mask when their DHCP server isn’t reachable.

A

APIPA

169.254.

19
Q

If you were to look at your ipconfig, and you see that your IP address starts with 169.254, what does that mean?

A

You’ve been assigned an APIPA address; DHCP server unreachable.

20
Q

If you’re not able to access a Windows share, what are two likely reasons for it?

A

If you’re not able to access that share, it could be because the server itself is currently unavailable, there is a problem with the DNS server, or someone may have modified your access permissions.

21
Q

If you’re not able to access your email, what things could be at fault?

A

Servers down

Network path

22
Q

If you are having problems accessing different resources on the network, you may want to check the system tray in Windows. It may tell you that you’re having ___ connectivity.

A

limited or no

23
Q

If the DHCP server is working properly and you were assigned a DHCP address, then you can try the different pings to your___, your ___, and then ___ to see exactly where along the line you’re having the communication problem.

A

local IP address

default gateway

outside your local network

24
Q

Pinging your local IP address, default gateway, and outside your local network are handy tools for troubleshooting what things?

A

DHCP/DNS/limited connectivity issues

25
Q

If we have a broken LAN icon in that system tray, then we have a ___.

A

loss of signal

26
Q

If you see a broken LAN icon in system tray, what should you check?

A

It indicates signal loss; check the cabling used to connect to the network. If that’s fine check NIC. If that’s fine check switches and WAPs.

27
Q

Intermittent connectivity could be caused by what network equipment failure?

A

Switch or a WAP randomly rebooting and causing us to have intermittent network connectivity.

28
Q

If you have some devices that are statically assigned and some devices that are DHCP-assigned, you may run into this conflict.

A

Two devices trying to share same IP address.

Windows will display a message saying there is an IP address conflict with another system on the network.

29
Q

If for some reason you’re able to get the same IP address on two workstations on the same network, you’ll find that the devices work intermittently. One device will work during certain times and the other device during the other. What is a quick way to resolve this?

A

Reboot or reset the NIC in one of the devices to restart the DHCP process.

30
Q

Another networking problem that can be very difficult to troubleshoot is the network is slow. This might be because…

A

the infrastructure devices themselves are overwhelmed.

older router or an older switch, etc

31
Q

Another quick check when your network is performing slowly is to check the speed and the duplex of your local interface. You may find that you’re running at 100 megabits instead of gigabit. Or you may be set to ___ instead of ___.

A

half duplex

full duplex

32
Q

One thing to always check when troubleshooting slow network connectivity is the ___ and ___ for incompatibility between the two.

A

speed and duplex

33
Q

On wireless networks, this may be caused by weak signal or radio interference. Are you too far from the Wi-Fi access point? Is transfer speed higher when you’re closer to the access point? The network is usually shared between multiple devices that share the available bandwidth.

A

Slow transfer speeds

34
Q

How do you configure duplex in Windows?

A

Network and sharing center -> connections -> If speed is less than 1.0 Gbps Click ‘Properties -> advanced -> change to 1.0 Gbps Full Duplex or Auto Negotiation

35
Q

On wireless networks, this may be caused by weak signal or radio interference. Are you too far from the Wi-Fi access point? Is connectivity more stable when you’re closer to the access point? To avoid interference, access points can change the used radio channel frequency. Try restarting the access point to allow it re-select the channel. Try manually reconfiguring the channel.

A

Low RF signal

36
Q

If you have previously configured a Wi-Fi network, but now the SSID is not working, you’re either…

A

out of range of the access point with this network, or the access point configuration has been changed and the SSID is no longer available.

37
Q

What is SSID?

A

SSID is Service Set Identifier. It is the name of a WiFi network that users see when they are scanning for networks to attach their devices to.

38
Q

An “SSID not found” can cause what? What is a possible way to rememdy? it?

A

No wireless internet access. Reconfigure the Wi-Fi connection to another SSID. Check if SSID is set to hidden.

39
Q

What is a possible cause of Low RF signals when in close proximity to other wireless networks? How can you remedy this?

A

Interference from other wireless networks using the same frequencies. Change the broadcast channel.

40
Q

When troubleshooting issues with signal strength, what are some things to examine?

A

look at the transmitting signal from your access points

look at the transmitting antenna

Move WAP closer to users, away from flat surfaces

make sure that you’re on the same channel as your access point; if it is set to manual change to automatic.

41
Q

What are some common things that can cause wireless interference?

A

microwave ovens

cordless phones

florescent lights

generators

42
Q

What does it mean to disabled SSID advertisement?

A

Your network name will not appear in a list of available wireless networks. Can manually type in SSID to connect.