1. A method for providing a firewall service in a computer network comprising the steps of: forming an augmented set of rules by including in a currently-loaded initial set of access rules at least one rule which acts to alter the operation of the currently-loaded initial set of rules under specified conditions without reloading at least one unaltered rule of the currently-loaded set of access rules; and using the augmented set of rules in validating a packet; wherein the at least one rule is a dynamic rule and further wherein the dynamic rule has associated therewith at least one set of data which is pointed to by the dynamic rule, such that the data within the set can be changed to alter the operation of the rule without changing the rule itself.