Enhance network security with dynamic packet filter

This paper presents the study, design and implementation of a firewall, in particular a major component of a firewall: the dynamic packet filter. A packet filter may be static or dynamic. A dynamic packet filter checks, on the fly, the outgoing IP packets from a computer and then allows incoming packets to get through the packet filter if the packets are from the same computer as the outgoing packets were sent to. There are currently no dynamic packet filters on the Linux operating system which has been chosen to be the development and test environment due to the source code availability. Some performance measurements have also been obtained to show that a safe system does not necessarily have to be very slow. This might otherwise be of some concern, as there is a trade-off between the security and the performance of the system