Abstract: This specification describes a system that can offer, among other advantages, dynamically allowing or rejecting non-DHCP packets entering a switch. In addition, a FDB is commonly used by a bridge or switch to store an incoming packet's source MAC address and its port number, then later on if the destination MAC address of another incoming packet matching any entry in FDB will be forwarded to its associated port. Using the techniques described herein, not only this will be completely transparent to user, the techniques can also result in an increase in switch performance by blocking unwanted traffic at an earlier stage of forwarding process and freeing up other processing units at a later stage, like switch fabric or packet processing stages.