switch troubleshooting , urgent

[carl_townshend]

Hi all, I had a massive problem today with 6 of my switches, They basically were all flashing off and on like mad. all in sync. The problem was intermittant so its still left as is. wE Checked for virus etc but there were none, Is there anything on the switches that can tell me whats going on or how I should trouble shoot this type of prob.

thanks for youe help

[Bobby Thekkekandam]

I'd start by checking for high CPU utilization, abnormally high traffic counters, and syslog messages.

Beyond that, I'd need more info. From the sounds of it, you're probably looking at a broadcast storm, some sort of flooding, or layer 2 loop.

HTH,

Bobby

[carl_townshend]

if it was looping surely spanning tree would stop this ? it was about 6 of my switches all flashing the same, we did a packet capture on the lan but couldnt find anything !!

[sean]

Loop is possible, depends on how you have your spanning tree setup. I would set up a couple of span ports to sniff traffic. Just dump it to a box.