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Interfaces on a switch

What makes an interface on a switch go up?

Hall of Fame Super Blue

Interfaces on a switch


That is a very general question so the general answer is a connected device that is up should make port on the switch go to up/up. However there are many things that could stop this happening eg.

1) the port is administratively shut down

2) the wrong type of cable was used

3) port security shuts the port down

4) 802.1x authentication fails and shuts the port down

5) an STP BPDU received on a port configured to err disable if it receives a BPDU

etc.. I am sure others can add to the list. So, assuming the port is not shutdown, the cable is not faulty and nothing extra has been configured on the port a device (whether an end device such as a PC or server etc, a router, another switch) that is up and connected to the port should then bring that port to up/up.


Hall of Fame Super Gold

Re: Interfaces on a switch

6)  Cable not terminated properly.

7)  Faulty port (client NIC or appliance port).

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