A network firewall is a device placed between networks of different trust levels to filter authorized and unauthorized packets.
This is done by sequentially checking a packet against a set of rules until one that matches the packet is found.
A set of rules for filtering packets configured on the firewall. These are derived from the security policy of the organisation.
Each rule specifies the action to be applied to the packet - ALLOW or DENY entry into the network
Sequential evaluation of rule sets to find a matching rule for the packet reduces matching time; negative impact on filtering performance
Reducing the inspection time by applying less rules to packets is one solution investigated in this research