Microsoft Internet Security and Acceleration Server 2004 SDK

IFWXFilter

The IFWXFilter interface is used by the Microsoft Firewall service to load and initialize a filter and to create session filters. An IFWXFilter interface is called for each filter that is in ISA Server storage and is enabled.

When To Implement

Every application filter must implement this interface. When the Firewall service starts, it creates an instance of the filter object for each application filter that is installed on the ISA Server computer and enabled.

Methods in Vtable Order

The IFWXFilter interface inherits the methods of the standard COM interface IUnknown.

In addition, IFWXFilter defines the following methods.

Method Description
FilterInit Initializes the filter and passes it a pointer to the IFWXFirewall interface exposed by the Firewall service. This interface provides access to Firewall service functions that are not tied to any specific user session.
FilterShutdown Begins the shutdown sequence for the filter object when the Firewall service is shutting down.
AttachToSession Called by the Firewall service when it determines that a session filter is needed.

Remarks

Only one instance of the IFWXFilter interface is created per filter. In the IFWXFilter interface, you define a port, or range of ports, to be monitored, and the events that will trigger a call to the IFWXFilter::AttachToSession method.

Requirements

Server: Requires Windows Server 2003 or Windows 2000.
Version: Requires Internet Security and Acceleration Server 2004.
Header: Declared in Wspfwext.idl.

See Also

Filter Interfaces