Filtering of all IP version 4 (IPv4) and IP version 6 (IPv6) traffic entering or leaving the system. By default, all incoming traffic is blocked unless it is a response to a previous outgoing request from the computer (solicited traffic) or unless it is specifically allowed by a rule created to allow that traffic. By default, all outgoing traffic is allowed, except for service hardening rules that prevent standard services from communicating in unexpected ways. You can choose to allow traffic based on port numbers, IPv4 or IPv6 addresses, the path and name of an application, the name of a service that is running on the computer, or other criteria.
Protecting network traffic entering or exiting the computer by using the IPsec protocol to verify the integrity of the network traffic, to authenticate the identity of the sending and receiving computers or users, and to optionally encrypt traffic to provide confidentiality.
In previous versions of Windows, implementations of server or domain isolation sometimes required the creation of a large number of IPsec rules to make sure that required network traffic was protected while still permitting required network traffic that could not be secured with IPsec. This complexity is eased in Windows Server 2008 R2 by a default behavior that results in a more secure and easier-to-troubleshoot environment.