Do you have a Cisco router for your default gateway? If so I suggest you enable and look at the route cache to find the offending computer.

To do this go under the ethernet interface in configuration mode and enter "ip route-cache flow"

Then exit the config mode and enter "sh ip cache flow" from the enable prompt.

The router will display all sessions by what computer is starting them. Probably one spyware / virus ridden device is killing your network by trying to propagate.

Thanks for your help W1r3sp33d. Think I've identified this as faulty wiring from the patch to the wall ports. Everytime someone connects to that wall port the comms start dropping out, and the switch locks out the port.

We've got a comms team coming in shortly to check it out, so hopefully this will be resolved, but I'm greatful for you help in the investigation


David

glad you isolated the problem, hope the tips helped finding it. Cheers!