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network cable problem

by techie36 / December 1, 2008 8:45 AM PST

I am having problem with some of my network drops in my school network. Approximately 40 cable drops from the ceiling in classrooms have quit working all of a sudden. The other 60 or so seem to be working just fine. I can not seem to track down any other problem with the switches or the router. I have ran a network cable to an active drop which works just fine. I would not have a problem rerunning all of the cables except for the fact that I find it odd that several have gone out instead of just a few. Any advice would be greatly appreciated.

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Where and how do they terminate?
by Steven Haninger / December 1, 2008 8:54 AM PST
In reply to: network cable problem

Do they go to a patch panel and are they labeled so you can test them individually? Do you know if the ones gone bad might run through a common location? Perhaps over something that gets very hot? This might sound not to be possible but animals hiding in ceilings and other nooks and crannies of a building can damage wiring.

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Network cable problem
by techie36 / December 1, 2008 10:26 PM PST

I have looked in the ceiling and can not seem to find anything. The cables are away from the heating ducts. When you plug the cables into the computers they light up on the switch, but they will not ping anything and will not pick up an IP that is correct. Very frustrated at this point.

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Are the dead cables all connected to the same switch?
by Steven Haninger / December 2, 2008 7:01 AM PST
In reply to: Network cable problem

If so, that could mean loss of connection to the router or that the switch has gone bad. You could try giving static addresses to a few PCs on the suspect cables and see if you can ping those addresses from other PCs. If that works, I'd be looking at the relay rack. If the switch is not of the auto-sensing type, perhaps the button for the uplink port has been tampered with.

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Network cabling problem
by techie36 / December 2, 2008 10:48 PM PST

I have tried assigning static IPs, but it still won't connect. I have almost come to the conclusion that the cables are not the problem. It seems to be one hallway that is out. However, some of the drops show to be sending and receiving traffic on the switch, they won't connect though. When I run the ipconfig on them, it gives them a 169 address. Won't ping the router, etc... I am wondering if we have something else going on. What do you think?

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169 is the self assigned address.
by R. Proffitt Forum moderator / December 2, 2008 11:17 PM PST

You do know what this means?

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by techie36 / December 3, 2008 2:51 AM PST

What are you thinking?

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It's a default and non-working address
by Steven Haninger / December 3, 2008 5:34 AM PST
In reply to: what?

that's created internally. You won't get a Basically it means no address has been assigned by yourself or as requested by the device.

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So you have blinking lights
by Steven Haninger / December 3, 2008 1:43 AM PST

Do you have everything labeled so you can trace wiring from a PC to the relay rack (presuming you use such)? Might this hallway have a switch located away from the main network closet area? If you unplug all the cables from the non working PCs, does each disconnect cause an LED to go out on a switch and is it the same switch? I do some volunteer work at a school and we did have a lightning strike that took out several ports in one switch leaving others unaffected. Any electrical "event" lately?

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Electrical problem
by techie36 / December 3, 2008 2:49 AM PST

The electrical issue is kind of what I have been thinking too. Yes, the patch panel is labeled and when you plug the computers in the lights light up, but no connectivity. We had power surges around the time this happened that blew transformers on our wireless tower. The question is, how do I determine if that is it?

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Can you reach the router from one of the dead drops?
by Steven Haninger / December 3, 2008 5:31 AM PST
In reply to: Electrical problem

If you can patch directly into the router with some of the individual cables and you get an internet connection, I'm thinking the problem may be with the switch. It's possible some ports work and some don't. It may also take a close examination of the relay rack wiring. I've seen loops between switching components to reek havoc. As well, managed switches that allow ports to be turned on and off or locked to MAC addresses can be an issue. I've not dealt with anything that sophisticated so cannot offer much in that regard. If your network drops terminate at a patch panel, just run a cable right to a router LAN port and see if you can connect. Good luck.

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