Microsoft Internet Security and Acceleration Server 2000


A data-filter object may implement the IFWXSlowDataFilter interface to prevent premature termination of the connection.

Methods in Vtable Order

IUnknown Methods Description
QueryInterface Returns pointers to supported interfaces.
AddRef Increments the reference count.
Release Decrements the reference count.

IFWXSlowDataFilter Methods Description
OkToTerminate Verifies that all data for this connection has been processed.


This interface is implemented by the application filter.


When a Firewall client application calls the Winsock WSACleanup function, the client DLL will close the Firewall service session. As a result, the Firewall service will terminate all the connections that were created in this session.

In rare circumstances, this may lead to data loss, if the client application relies on TCP/IP for receipt acknowledgement. The connection could be closed after acknowledgement of a packet receipt because the slow connection delays the receipt of the remainder of the packets. This is not an issue if the client application uses application level acknowledgement.

To prevent data loss in these cases, implement the IFWXSlowDataFilter interface.


  Windows NT/2000: Requires Windows 2000.
  Version: Requires ISA Server 2000.
  Header: Wspfwext.idl.