These rules open, lock, and time all aspects of the each session. This ability to adapt to network traffic provides a distinct advantage over ordinary static packet filtering, a widely used technology which can leave networks vulnerable to attack by intruders or hackers. Introduction This paper explains the network security benefits of dynamic firewall technology by comparing its screening process to that of static packet filtering. The paper includes background information on FTP protocol as an enhancement to this comparison. A short guide to the step by step communications between a remote user and a network FTP server illustrates why network security is vulnerable in an FTP session .
All data traversing the Internet is divided into bundles called packets.
Each packet conforms to a specific structure which allows the network elements of the Internet to successfully route a packet from its source to its destination. All the information needed for routing and for delivery to the appropriate application at the receiving end is contained in IP headers, which are added to each packet of data at various steps as it enters the network. Networking protocols on the Internet generally include four layers, Application, Transport, Network , and Data Link . In simple terms, each packet's user data and headers indicate what the user wants and where the packet should go. Packets can travel across network boundaries, from an internal host to an external host or vice versa.