12.1 File Services Overview
The Microsoft Windows® Firewall provides host-based firewall protection for computers running Windows® XP operating system, Windows Server® 2003 operating system, and Windows Vista® operating system. Windows Firewall is designed to be a supplemental security solution. Windows Firewall should be part of a comprehensive security architecture that implements a variety of security technologies, such as border routers, perimeter firewalls, intrusion detection systems, virtual private networking (VPN), IEEE 802.1X authentication for wireless and wired connections, and Internet Protocol security (IPsec).
Windows Firewall inspects and filters all IP version 4 (IPv4) and IP version 6 (IPv6) network traffic. It is a stateful firewall, which means it tracks the state of each network connection and determines whether incoming packets should be allowed or blocked. Windows Firewall blocks incoming traffic unless it is in response to a request by the host (in which case, it is solicited traffic) or has been specifically permitted by being added to the Windows Firewall exceptions list. Aside from a few Internet Control Message Protocol (ICMP) messages, Windows Firewall allows all outgoing traffic.