loop prevention and identify which switch goes error

[petercinvest]

we have two switches stacked together, both using ip 10.2.3.1. so when error comes, the log only say G1/0/25 port error, so how do we know which switch it goes wrong?

if i use one cable direct connect two data port, it cause loop and switch is down, how to make configuration to prevent this to happen? thanks

[James Qin]

Run show version

This tells you the order of the switch by matching "System serial number" to the label on the switch.

G1/0/25 meaning this is port 25 on switch 1.

Configure spanning-tree bpduguard enable on all your ports will prevent loops by shutting down the port.