BPDUFilter
Another helpful command to use with PortFast is BPDUFilter. Since a switch port that has
PortFast enabled will still receive BPDUs by default, you can use the BPDUFilter to stop
BPDUs coming into that port completely. BPDU filtering not only blocks just the BPDUs, but
it takes the port out of PortFast status and forces the port to be a part of the STP topology
again.
S1(config-if-range)#spanning-tree bpdufilter ?
disable Disable BPDU filtering for this interface
enable Enable BPDU filtering for this interface
S1(config-if-range)#spanning-tree bpdufilter enable