Windows Filtering Platform


Windows Filtering Platform (WFP) is a set of API and system services that provide a platform for creating network filtering applications. The WFP API allows developers to write code that interacts with the packet processing that takes place at several layers in the networking stack of the operating system. Network data can be filtered and also modified before it reaches its destination.

By providing a simpler development platform, WFP is designed to replace previous packet filtering technologies such as Transport Driver Interface (TDI) filters, Network Driver Interface Specification (NDIS) filters, and Winsock Layered Service Providers (LSP). Starting in Windows Server 2008 and Windows Vista, the firewall hook and the filter hook drivers are not available; applications that were using these drivers should use WFP instead.

With the WFP API, developers can implement firewalls, intrusion detection systems, antivirus programs, network monitoring tools, and parental controls. WFP integrates with and provides support for firewall features such as authenticated communication and dynamic firewall configuration based on applications' use of sockets API (application-based policy). WFP also provides infrastructure for IPsec policy management, change notifications, network diagnostics, and stateful filtering.

Windows Filtering Platform is a development platform and not a firewall itself. The firewall application that is built into Windows Vista, Windows Server 2008, and later operating systems Windows Firewall with Advanced Security (WFAS) is implemented using WFP. Therefore, applications developed with the WFP API or the WFAS API use the common filtering arbitration logic that is built into WFP.

The WFP API consists of a user-mode API and a kernel-mode API. This section provides an overview of the entire WFP and describes in detail only the user-mode portion of the WFP API. For a detailed description of the kernel-mode WFP API, see the Windows Driver Kit online help.

Developer audience

The Windows Filtering Platform API is designed for use by programmers using C/C++ development software. Programmers should be familiar with networking concepts and design of systems using user-mode and kernel-mode components.

Run-time requirements

The Windows Filtering Platform is supported on clients running Windows Vista and later, and on servers running Windows Server 2008 and later. For information about the run-time requirements for a specific programming element, see the Requirements section of the reference page for that element.

In this section

Topic Description
What's New in Windows Filtering Platform
Information on new features and APIs in Windows Filtering Platform.
About Windows Filtering Platform
An overview of Windows Filtering Platform.
Using Windows Filtering Platform
Example code using the Windows Filtering Platform API.
Windows Filtering Platform API Reference
Documentation for the Windows Filtering Platform functions, structures, and constants.

Additional resources

To ask questions and have discussions about using the WFP API, visit the Windows Filtering Platform Forum.

Kernel-Mode Windows Filtering Platform API - Design Guide

Kernel-Mode Windows Filtering Platform API - Reference

Windows Firewall with Advanced Security

WFP Diagnostics Extensible Helper Class

Winsock Secure Socket Extensions