Explanation:
Windows Firewall
Windows Firewall is a packet filter and stateful host-based firewall that allows or blocks network traffic according to the configuration. A packet filter protects the computer by using an access control list (ACL), which specifies which packets are allowed through the firewall based on IP address and protocol (specifically the port number). A stateful firewall monitors the state of active connections and uses the information gained to determine which network packets are allowed through the firewall. Typically, if the user starts communicating with an outside computer, it remembers the conversation and allows the appropriate packets back in. If an outside computer tries to start communicating with a computer protected by a stateful firewall, those packets are dropped automatically unless access was granted by the ACL.