A few weeks ago a Catalyst 3560 seemingly randomly stopped passing through traffic. I have gone so far as to format it's flash and xmodem up a new copy of iOS, as well as clearing the nvram, and yet the switch simply won't pass through traffic.
It's connected to a Juniper EX4200, and it's port is working fine.
I used Wireshark to look at the traffic on the network, and I can't even see any of the broadcast packets from the other devices on the switch. (Edit: It seems I can see SOME broadcast packets, but not as many as I'd expect...)
I'm lost as to what to do... it's like each port is totally isolated, and the only traffic I see are the packets from my own device, as well as some packets from the switch itself.
I should add, something weird happened around the same time that this switch started behaving like this:
The EX4200 that this switch is plugged into, is a pair in a virtual chassis, and at around the same time this Catalyst 3560 started misbehaving, the same sort of thing happened with the EX4200s, except those were only on ports where NEW devices were plugged into. The ports where devices had been connected to before, still operated normally. A power cycle fixed this issue on the Junipers, however I've power cycled, reset and reflashed the Cisco Catalyst with no luck.
I'm at a loss. I have no idea what happened to these switches, and why a reboot fixed one, and the other seems to be totally stuck.
It must be misconfiguration it... but how? IIRC, without a config, or with the basic config, these switches just act like switches... don't they?
I haven't done Cisco stuff in more than 10 years, so I may be making an obvious mistake.
Any help would be appreciated.
