Protocol filtering can be configured on Catalyst 4000, 5000, or 6000 series switches.
Protocol filtering does not require any special feature cards on the switch to operate.
Protocol filtering enables you to configure a port to filter or block flood (broadcast, multicasts, and unknown unicasts) traffic based on protocols.
Protocol filtering is only supported on Layer 2 access ports and cannot be configured on trunk links or Layer 3 ports.
Protocol filtering supports blocking of IP, IPX, AppleTalk, VINES, and DECnet traffic. All other protocols are not affected by protocol filtering.
Administrative protocols such as Spanning Tree Protocol (STP), Cisco Discovery Protocol (CDP), and VLAN Trunking Protocol (VTP) are not blocked ...