Lesson 4 - Chapter 5: Troubleshooting Networks Flashcards
Someone yells, “The network is down!” What’s the first place you should start troubleshooting?
start at the physical level to rule out connectivity as the source of the problem
When a Windows PC is connected to a wired network, how does it appear in the notification area?
It shows up as a monitor with a cable next to it
When a Windows PC is disconnected from a wire network, what does the icon look like in the notification area?
A globe with a crossed-out “no” symbol
If you see the globe icon for a wired connection, what are 2 obvious things to check?
- Is a cable unplugged or damaged at any point?
- Is the switch or router powered up and operational?
If you see the globe icon for a wired connection, after checking the 2 obvious things, what basic troubleshooting do you perform next?
Reboot everything (PC, switch or router, and cable modem)
With physical LAN connectivity issues, after checking obvious things and rebooting when you see the global icon, what’s the next step in checking for hardware problems?
Check the link lights on the NIC and switch to see if they’re lit (or ask the user to check the lights for you)
What’s a question to ask yourself when determining the scope of the problem?
Is it just this PC or all PCs connected to the same switch/router having an issue?
Multiple PCs failing to access the network often points to what kind of problems?
often points to hardware problems at the switch/router (or server if it’s a domain-based network)
What do you check if the network fails in an office with a structured cabling system?
Determine if the wall outlet or its cabling is faulty by connecting the no-network system’s NIC directly to a known-good network port in another office to see if it works with a tech’s own long patch cable
(if network connectivity works, suspect the patch cable running from the first outlet to the switch)
A bad ___ can cause a lack of connectivity
a bad NIC
What are 4 ways to use software to troubleshoot a bad NIC? Windows and macOS
- Windows: Device Manager > Check NIC’s status
- Windows: Network Troubleshooter utility (Find and Fix Network Problems)
- macOS: Apple > System Settings > Network > Check status
- NIC came with diagnostic software? Run it
What part of a NIC is a common failure point?
the NIC’s female connector
NICs that come with diagnostic software often include a special test called what?
often include a special test called loopback test
What’s a loopback test?
it tests the NIC by sending data out of the NIC and checks to see if it comes back
(some NICs perform only an internal loopback which tests the circuitry not the connection pins)
What’s a loopback plug?
A plug inserted into the NIC’s port in order to do a true external loopback test
What do you do if the NIC is bad? (2)
- Replace it
- If built into the motherboard, disable it in BIOS/UEFI and replace it with a PCIe or USB model
How do you diagnose bad horizontal cabling run, and whether the cable is disconnected and where?
with a mid-range time-domain reflectometer (TDR) tester
(such as the Fluke Microscanner)
What does a time-domain reflectometer (TDR) tester measure?
it measures impedance in network cabling
(if it measures any impedance, something is wrong with the cable)
How do you use a TDR tester?
You unplug the patch cable from the PC, and attach the tester OR you unplug the patch cable from the switch and plug the tester into that patch cable (complete test this way)
What do you do if horizontal cabling is bad?
Call your local installer. If it’s bad in one spot, it’s probably bad in another and needs replacement.
What does it mean to trace cables?
identify
What device do you use to trace cables?
toner