This is my first post in this site. I'm studyng to take the BCMSN 642-812, and i have a doubt of the feature "BPDU Filtering" prevent the interface that are in port-fast to SEND and RECIVE BPDUS???? I search it in cisco.com but it only say that prevent sending bpdu. It doesn't tell anything of reciving them.
What this command does, is enable bpdufiltering automatically on all ports that have "portfast" enabled. If portfast is disabled, then BPDU filtering will not be enabled on that port. In global mode, the port will not send BPDUs, however, if the port receives a BPDU the port losses the portfast feature and behaves normally. BPDU filtering is now disabled.
To enter per interface, use the following command:
(config-if)#spanning-tree bpdufilter enable
What this command does, is enable bpdufiltering on the port and the port will not send any BPDUs nor will it process any BPDUs it receives. It basically drops all received BPDUs.
Notice the different configuration modes in the above commands. Cisco recommends to use this feature with extreme caution, as bridging loops can/may occur.