A type of firewall which relies on tracking the status of a networkconnection and a rulebase. The handshake at the start of a networkconnection is observed and monitored, and if a successful connection isestablished, the firewall then makes an entry in a table to allow allfuture traffic for that connection to pass freely. The advantage is that avery high degree of security can be achieved and virtually allnetwork based attacks can be thwarted with minimal performance impact.Many stateful inspection firewalls also provide some application proxycapabilities for various types of network traffic. This allows them tofilter requests and screen content.Transmission Control Protocol/Internet Protocol (TCP/IP)These are network protocols used to communicate over the Internet. IPdefines how a packet of information can be exchanged and routed across thenetwork. TCP uses IP to allow two systems to establish a session (similarto a telephone conversation), in order to exchange or transfer data.