Dynamic Packet Filtering
Dynamic Packet Filtering is also referred to as stateful firewalling. Here the firewall maintains the status of connections as well. When a connection is made the information about the connection is stored in the memory. The filter scans the packets coming from that connection for any harmful payload. After which it calls that connection as a secure connection and any packet coming from that connection is allowed to pass without further processing. For example, if a link on a Web page is being clicked, an HTTP request is made to a specific URL address. At first packets coming back from that address would pass through the stateful inspection, checked and after ensuring that the connection is secure all later packets coming from that web server are allowed to pass which is a performance gain over static filter.