Have you ever looked at a comms cabinet run of Cisco switches only to find that ever interface is patched, some of them have no link lights and you don’t know which ones can be unpatched. The below steps are my method finding which interfaces have not been used in a long time. There are plenty of tools and network monitoring solutions that could be used, the below is the native IOS method.
If you run show interface against an interface the output includes details on the last time the interface received or sent data. In the case of the below screenshot 7 weeks.
But if manually checking interface after interface does not sound fun then the below regex after the show interface command will return a list of all interfaces that haven’t been used in the last 6+ weeks or have never been used.
show int | i proto.*notconnect|proto.*administratively down|Last in.* [6-9]w|Last in.*[0-9][0-9]w|[0-9]y|disabled|Last input never, output never, output hang never
The command will give an output similar to the below;
I generally run this command and then do a show interface to check the detail and description to make sure I haven’t missed anything before un-patching the interface.