Tracking Down Source of Network Instability
Feb 8
If the issue happens, it happens at 10am, for about 1minute between onset and return to stability. It does not happen every day. During the minute, pings go through the roof and packets start to drop, then the pings settle down and packets stop dropping, everything is fine again. This occurs on our wifi to the point that wifi users effectively loose internet, signs of the issue are visible on the wired network but don't impact it to the point that people really notice. We have dual internet connections from different providers configured in round-robin, it doesn't seem to care who we are on.
We audited through IT's automated processes and couldn't find anything running at 10am. We've kind of tried to watch the network but our tools are limited, nothing seems to be obviously surging through at the firewall, but we may not be doing the right kind of reporting.
At this point I'm ready to schedule my day around it and start unplugging a target system the moment I see it start to happen to see if that stops the issue in its tracks.
But I wanted to see if anyone has tool or methodology suggestions.
1 answer
Accepted answer · original discussion
Feb 8
I would suggest you to rather start with network analysis tools like tcpdump and Wireshark. Then
you would know if this is a network caused problem or
a physical source one.
Is your network protected against physical loops ( through for example a user who would inadvertantly plug an Ethernet cable within 2 different sockets )? If not you would see a symptomatic STP storm with the above mentionned tools.
Is there some electrical engine started at 10am which may cause electromagnetic interferences with any wireless or wired network? If this is the case you would see a lot of frame with bad checksums.
Your perspective belongs here.
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Feb 9