Ndis IM driver not usable on WXP bridge

Discussion in 'Windows Vista Drivers' started by Peter, Aug 14, 2006.

  1. Peter

    Peter Guest

    It seems that ndis IM driver created by documented way is not usable on WXP
    bridge. Packets for both incoming and outgoing directions are in IM driver
    appeared like incoming and IM driver is bound only to adapter "MAC bridge
    On W2K3 the behavior is OK and IM driver is bound to "MAC bridge miniport"
    and also on two ethernet adapters and it is usable.

    Is WXP bridge designed to not be usable with ndis IM driver ?
    Why should not write it in documentation ?

    Peter, Aug 14, 2006
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  2. The Network Bridge is a MUX IM driver. So FilterClass will not control
    bindings. You may need to write a supporting Notify Object to install the
    way you want if the Windows Network Bridge is installed.

    From what I have seen the way a NDIS IM filter driver which does not have a
    NO will bind to the Network Bridge is not deterministic. In general,
    however, if the bridge is installed before the IM driver it is likely that
    your IM filter will bind above the MAC Bridge Miniport _and_ also below the
    MAC Bridge on each of the lower-level bridge port miniports. If the IM
    driver is installed _before_ the bridge, then the binding is different.

    Although the FilterClass will not actually control the binding to the
    NetworkBridge, the FilterClass may influence the binding to some degree. Try
    using the falilover class.

    In any case, a NDIS IM filters _can_ be bound above and below the Windows
    Network Bridge on both Windows XP and Windows Server 2003.

    Good luck,

    Thomas F. Divine, Windows DDK MVP
    Thomas F. Divine [DDK MVP], Aug 14, 2006
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  3. Moreover, the Bridge driver itself probably also has a Notify Object,
    which might prevent other intermediate drivers (or protocols in
    general) from binding to adapters.

    Note that if there is more than one IM, their NOs can be in conflict
    wrt which bindings they allow or disallow. So that can IMHO always lead
    to severe problems if NOs are too restrictive. Thus, an NO should be
    written somewhat defensive.

    Stephan Wolf [MVP], Aug 15, 2006
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