One of the technologies, that the Internet Protocols team works on, is the Windows Filtering Platform. This is a new architecture and a set of APIs and system services that enables application developers to build applications, such as, firewalls and antivirus software. Firewall, anti-virus vendors and ISVs are encouraged to take advantage of these APIs instead of unconventional hooks and custom solutions based on reverse engineering the TCP/IP protocol stack. In addition to the APIs, WFP provides a way to plug-in call out modules for deep packet inspection.  More information on Windows Filtering Platform can be found at the following links:

http://www.microsoft.com/whdc/device/network/WFP.mspx

http://windowssdk.msdn.microsoft.com/library/default.asp?url=/library/en-us/fwp/fwp/fwp_mgmt_functions.asp