my network completely crashed down due to a bridgning loop.
Somebody connected a linksys unmanaged switch to an access port. The access port has portfast configured and bpduguard enabled.
At first the port fastly turn in an err-disabled state because of the bpduguard function. after a while the ports tries many times to recover and always come back to an err-disable state.
at a certain point the linksys switch probably collapses and stops sending many packets included BPDU Packets.
at this point the port in my cisco catalyst recovers from the err-disable (bpduguard) state and turn into a forwarding state--> then catastrophe!!! the whole LAN is setteled down and I have to switch off all my catalysts and then power then one by one to find the looped port.
Isn't there any way to prevent this without recurring to port-secure functions?
I tried to disable bpduguard automatic recovering and it seems to work fine: the port is put into a permanent err-disabled state. but i don't know if there may be other unknown issues.
Would spanning tree loopguard default help in any manner?
thanks
Johnny
