Patent US 9,258,329

A network security appliance supports definition of a security policy to control access to a network. The security policy is defined by match criteria including a layer seven network application, a static port list of layer four ports for a transport-layer protocol, and actions to be applied to packet flows that match the match criteria. A rules engine dynamically identifies a type of layer seven network application associated with the received packet flow based on inspection of application-layer data within payloads of packets of the packet flow without basing the identification solely on a layer four port specified by headers within the packets. The rules engine is configured to apply the security policy to determine whether the packet flow matches the static port lists specified by the match criteria. The network security appliance applies the actions specified by the security policy to the packet flow.