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Network problems on network in school. PC's keep saying network cable unplugged.

I am the technician working in a school with a network of about 60 machines.
The school has recently transferred from an old school into a brand new school. The new school has brand new network switches and connects to a fibre backbone that runs to the town hall.
The school has its own server.
I am currently in the Suite that has 30 brand new Dell Optiplex 755 PC's and they have all been ghosted from a perfect machine that was tested and working correctly before ghosting took place.
The machines are now playing up in a sense that you can be working on a machine, and surfing the internet without any problems, and then it comes up to say 'The network cable has been unplugged'
This only happens on certain machines, and they work fine when they want to, but then the problem reoccurs. Reboots do not affect this problem. The network chipset is 'Intel 82566Dm-2 Gigabit'.
Ive checked the switches but they all seem to be running fine.
Whilst writing this, the network card has come up to say its disabled, then re-enables itself and then connected back to the network, however this happens on top of the network cable unplugged issue.
Any ideas of where i should look for a solution to this problem?
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RikWilsonUK
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RikWilsonUK
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3 Solutions
 
allwyngCommented:
Update the network adapter driver software from the manufacturer's Web site.


Change the Link Speed and Duplex settings (using Device Manager) to use "100 Mbps Full Duplex" or "10 Mbps Full Duplex" instead of Auto Detect.
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RikWilsonUKAuthor Commented:
Could it not be a problem with the switches. The school has 3 switches, however only a certain number of machines are affected, so im currently trying to trace if they are all connected to the same switch. Could a switch fault cause this problem?
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allwyngCommented:
Yes if you have a managed hub\switch it could be a problem.  Trace the computers and find out if they are all connected to the same switch causing the problem.  That may give you an insite to the problem
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RikWilsonUKAuthor Commented:
I have traced the cables and yes they are only on 1 switch, i have connected them to a different switch, however am still getting the exact same problem
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JohnjcesCommented:
Without a doubt a bad port in a switch can cause a lot of grief and headaches.

When the error occurs, go to that switch and that failed port connected to that PC and plug it into another port.

I have also seen that occur when the Cat5e or 6 wiring was done poorly, terminated loosely and run right over the top of flourescent light transformers/ballasts esp when the runs are twice the suggested limit. COuple that with bad plug end temrinations and problems can occur.

Step 1). Check switch.

Step 2). Check your wiring using a good LAN checker. If you don't have one, check your cable with whatever tool you have available. Re-terminate the ends.
a). Check the length and routes of the cable.

John

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RikWilsonUKAuthor Commented:
The cables are definately sheilded and are definately under the suggested length.
I have changed the settings to 100mb/full duplex as suggested however the problem is still the same.
I am at a loss, and if i had hair that i could pull (its short) i would be pulling it out!!!!!!
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JohnjcesCommented:
Did you check the  switch, unplug the offending cable/run/PC and plug it into a different port or on a different switch?

Get a temporary switch and plug them all into that one and uplink it to one of your main switches.

What kind/type of shielded cable was run? Basic Cat5e or Cat6 even plenum rated is not shielded with a tin or braided shield to protect all pairs. Of course there is high dollar cable that is and you may be using it.

And are the ends terminated well?

John
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JohnjcesCommented:
last thing to check is a 10% failure on new machine NICs.

Test by disabling the on board and adding a card and drivers.

John
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dprimeusCommented:
I just purchased three new Dell 755s with the same NIC that you are talking about and I have the same issue.  It must be some kind of bug or something in the NIC.  I ordered a different dell machine with a different NIC recently and tried it on the same connection and no problems.  I am working with Dell to figure out what is up.  It has to be those new Intel AMT cards that are in them.
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dprimeusCommented:
After a useless chat session with a Dell tech when I restarted the machine I noticed a new BIOS option on the Dell boot screen.  CTRL-P.  This brings you into the Intel Management Engine BIOS which apparently is part of the new fancy dell AMT NIC.  I disabled Intel ME State Control and poof no more problems.  While I can not use the new functionality at lease the NIC seems to work.  Thanks Dell.
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jaw1971Commented:
how did you change the password?? is there a secret way?
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troypatrickCommented:
The default password is "admin".  Pull the power and the cmos battery for 20 to 30 seconds.  It only accepts strong passwords.
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