Question: what is the difference between bpdu guard and bpdu filter?
Answer: As the name says, BPDU filter filters BPDUs in both directions. BPDU filter will prevent inbound and outbound BPDU but will remove portfast state on a port if a BPDU is received. ... On the other hand, BPDU Guard keeps an eye open for any BPDU's entering the interfaces that are enabled this feature.