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New Member

Finding a device on a switch.

I have inherited a network where the cables have either been mis-labeled or in some cases not labeled at all. How can I find out what switch port a device is connected to?

New Member

Re: Finding a device on a switch.


If it is a small switch or only a couple of users you are interested in then I would be tempted to use the old method of noting the existing linklight status of all the switch ports, disconnect the user and spot the difference at the switch. Plug the user back in and with luck watch the port go orange as STP runs.

If the situation is bigger, I would hire a wiring contractor to re-label the wires. They have gizmos that enable them to identify two ends of the same cable.

hope this non-techie answer helps.


New Member

Re: Finding a device on a switch.


if you don't want to check all LED's on the device, just type "sh port" (CAT OS) or "sh int" (IOS) in the privileged EXEC Mode. There you can see which port ist up or down (used or unused).

If you want to know which other Cisco devices are connected to your switch, type "sh cdp nei" or "sh cdp nei det" (both IOS) to check the names, ports and types of the connected cisco devices.

Good luck.

Best Regards,

Nikolaus Isele

Cisco Employee

Re: Finding a device on a switch.

Use 'show cam' or 'show mac-address-table' and locate the MAC addresses of the devices you want to discover.

New Member

Re: Finding a device on a switch.

Once you've determined the MAC addresses that you're interested in (from the 'show cam' or 'show mac-address-table' commands) you can use the ARP table from the router on that subnet to get the corresponding IP Addresses, which may make it easier to coorelate the port on the switch to the machine.

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