What is a security rule?

A security rule stands for principle upon which the packet either is passed thru or blocked. Each rule has its unique identifier or in other words usage priority. Identifier determines the order of application of rules to a packet received. The smaller is the priority value of a rule, the higher is its priority and the faster it will be applied when analyzing packets. Packet analysis is stopped when there is a security rule strictly determining whether the packet should be passed thru or blocked. In case that there is no rule that can be applied to a packet received it is checked for compliance with level of security of an interface it was delivered to. Summing up the above said, security rules are applied prior o checking a packet for compliance with level of security settings.

Important

• It is important to determine the order of applying security rules, when developing computer security system.
• All packets are blocked in emergency security level , regardless of security rules in use.