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School network going down after school, resetting switches fixes temporarily

Posted on 2014-09-04
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Last Modified: 2016-05-05
We have a school network that goes down after the kids leave.  People can't print or get to the internet.  
Resetting switches fixes temporarily, sometimes reset twice a day.
We have Meraki switches throughout the network
Attached is a wire shark capture while slow. had to change the extension to txt to upload.
aug28.txt.zip
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Question by:sgt_best
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by:Montoya
ID: 40303545
does it always go down at exactly the same time?
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by:sgt_best
ID: 40304230
It starts when the students leave.  If they are relased at 3 it goes down.  If they release at 3:40 it goes down then.
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marek1712 earned 500 total points
ID: 40308706
Check the following link: ICMPv6 'Multicast Listener Report' messages are flooding the local network. There are way too many messages of this kind sent per second.
Do the classroom's computers have Intel I217 NICs? People mention that it sends many of these packets while the computer is in the sleep state. Changing the following setting seems to help:
Disabling sleep in network adapter's advanced settings->power management works

Aside from that - I'd suggest to segment your network with VLANs. It may save you from similar issues in the future.
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by:sgt_best
ID: 40310564
Yes, they do have those NIC's.

This is what we have done so far.
disabled AMT & IP6
Removed nic driver
installed updated driver from Feb 2014
Did this to 88 machines

Have several hundred more that are going to be done through group policy today.
I'll also check on the power settings.

Will let you know what happens.
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by:marek1712
ID: 40310607
Wow, no wonder the network's been dying with hundreds of machines flooding single VLAN.
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by:sgt_best
ID: 40319810
Changing the power & network settings fixed the issue.  There were other issues such as network connected devices like door controllers showing that they were connected then disconnected every 2 seconds.  They were in a separate VLAN and this went away when the HP computer settings were changed.  Thank you so much.
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by:dts3909
ID: 41579343
We have the same "ICMPv6 'Multicast Listener Report" problem.  We would like to globally mitigate this and future similar problems at our HPE Procurve switches (or routers).  Any suggestions?  Thanks in advance.
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