All computers in the local area network can't access the Internet or visit each other

Failure phenomenon: An enterprise intranet, all computers through the switch and proxy server Internet, one day, all computers in the local area network can not be on the network, and the LAN all computers can not access each other.

Fault analysis and elimination: According to the phenomenon of failure analysis. This failure could be caused by a problem with the proxy server, a problem with the switch, a proxy server not being able to access the Internet, or a proxy server connecting to the switch. First check the proxy server, found that the proxy server can surf the Internet, and then check the switch, found in all the lights in the switch is constantly flashing, the switch power off, and then open the switch led back to normal, and then check the network, the network back to normal, you can access the Internet, troubleshooting.