Tips for L2/L3 Switches troubleshooting

Not many things can go wrong on Switch level, but issues are also difficult to troubleshoot there.

L3 Switching and Redundancy: VLANs and Routing will be the main section to check for issues on L3 switches(maybe L2 also)

Switch#show brief


Switch#debug terse <- Only show the debug message except HELLO message

Spanning Tree:

Switch#show spanning-tree

Switch#show spanning-tree detail

Switch#show process cpu

If the troubleshooting goes to dead end, try to shutdown interfaces based on “Switch#show cdp neighbors” output to find the loop.

If you find the above looks familiar, study the CCNP yourself, you might write some fancier ones 🙂


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