BPDU GUARD - Layer 2 security feature to terminate STP domain.
Port that have BPDU GUARD enabled will shut down port if it will receive incoming STP packet.
This function can be enabled at global level or at interface level.
Global level:
spanning-tree portfast bpduguard default
Interface level:
spanning-tree bpduguard enable
To view if BPDU Guard is enabled:
show spanning-tree interface <interface-number> detail
If
bpdu guard is enabled by default - global
bpdu guard is enabled - interface level