I have a list of old IP addresses of devices, they need to be switched to a new IP scheme. At each switch in the company there patch panels that patch to the switch. The patch panel is labeled with a letter and number like A-1. Is there a way that I can find out what switch and port that IP is going to. Then I would be able to find that corresponding patch panel port, and then the device to be able to Re-IP.


  • Why do you need to know "where" it is to re-ip it? You should be able to just remote into the device and do that. If you need to find the port on a given switch, get the mac-address and look for it on the switch's mac address table. – HAL Jan 20 '16 at 16:26
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide your own answer and accept it. – Ron Maupin Aug 7 '17 at 14:43

You scenario is rather obscure, but I can invent a reason to search for the physical device - no DHCP used + no remote access, some ancient devices etc.

OK, in Cisco terms:

you log into the switch and ping the IP address, afterwards you do

show arp | include *needed-IP*

and look for the MAC address of that IP. Then

show mac address-table | include *needed-mac-address*

will show you the port where your device is. If the port turned up to be uplink/downlink to another switch, you go upstream/downstream and do there

show mac address-table | include *needed-mac-address*

Repeat until found. And when found - alas, tracing cables is your next challenge :)

Hopefully, you don't have a lot of network devices...


Your layer-1 (cabling) labels really have no relation to the layer-3 (IP) addresses.

You can probably go into the network devices and look at the ARP and MAC address tables to figure out to which switch port a device is connected. Beyond that, you will need to trace cables and try to relate closet labeling to the labels on the floor jacks.

This is why using DHCP is so useful since you don't need to manually change IP addresses on the hosts.

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