Network switch strobing or flashing continuously


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I have a AT&T uverse modem connected to a router connected to a 16 port switch and 6 workstations connected to a port on the switch via cat5 cable..  I noticed that all the ports on the switch started blinking or strobing continuously.  Normally each port would only blink when a local lan request or internet request from the workstation.  But now all of the lights on the ports are blinking continuously or strobing.  I disconnected all of the workstation cables and found one, when I disconnected it, the blinking would stop.  So I replaced the cat5 connectors on each end of the cable, ran continuity tests, plugged it back in, and the blinking stopped for a few minutes then started again.  I disconnected other cables at the switch and found another one that would cause the switch blinking to stop when I unplugged it from the port.  So I replaced the cat 5 connectors on that cable at both ends, ran continuity tests and plugged it back in.  The blinking momentarily stopped on the switch but  started again.  I have unplugged every cable connected to a port on the switch, one by one, but now it keeps blinking.  Have I lost my mind.  What could be causing that?

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Without more troubleshooting on your part, the simple answer is too many chickens on the line. Please reduce the amount of poultry in your hen house. Another solution would be to sharpen every pencil you own.

Seriously though, setup A sniffer and see what is going on. It could be anything. Could even be the sun spitting radiation directly on top of the switch or a purple unicorn taking a poop.

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Clients talk to each other, that's a core part of having machines connected in a network.

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Sorry but you aren't very helpful with information. Within my babbling I told you what to do. If you don't understand or want a magic answer then look at my babbling.  All you have done is attempt to figure out the issue on the hardware layer, being that the issue isn't on the hardware layer, you need to look deeper....how to look deeper, how to look deeper...hmmm...oh try sniffing the traffic as I mentioned above.   A common sniffer is wireshark another common sniffer is colasoft packet capture...there are many more.  This little doc that I just found on google by searching "sniffing traffic" tells you how to accomplish such a feat.

 

If it is still over your head after reading that or you can't possibly fathom how to do it with that simple doc, please refer back to magic purple unicorns.

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what switch is this - is it managed/smart so you can look to see what might be going on?  Could be a loop, could be a broadcast storm, could be the machines you disconnect infected and sending out all kinds of traffic via broadcast/multicast that would send traffic to all ports.

 

sc302 suggestion of sniffing is right on target.. Since you have identified at least 2 machines that seem to cause the traffic - one of those would be a good place to install the sniffer and take a look at what its putting on the wire.  Or any of your other machines would work too if they are seeing the traffic from what your saying is happening on the port lights.

 

It could be a bad nic spewing out garbage that the switch doesn't know what to do with..  The odds of 2 machines nics both going bad seems low, but sure could be that.  Or it could be some unicorn poop got into the switch guts as well ;)

 

Take a sniff on one of these machines and then post it if you don't know how to interpret what wireshark shows you.

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when I disconnected it, the blinking would stop.

 

 

 

I guess that's good news then haha :laugh:

 

So network traffic then? lol

 

It would stop blinking for a few seconds whilst it negotiates stuff, Speed Duplex, Any network device worth its penny would be too quick to notice though.

 

Can you try a different modem/router/switch?

 

Something like torrenting would cause massive amounts of network traffic....

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