Unicast filtering????

NTDEV
1

My miniport driver sends unicast packets to NDIS with different MAC address
than that of the system…But my NDIS stack does not reject it and sends
it up to the app above. Its a windows 98 system. Is this the normal
behaviour???

I would also like to know when the NIC card receives a unicast packet with
the destination Mac ADDRESS field set to FF’s(broadcast) does the nic change
it to the mac address of the system or does it send the pkt as it is. Will
the stack above accept the pkt and if an app listens for unicast pkts Rx
these pkts???

Thanks
Daniel

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2

> I would also like to know when the NIC card receives a unicast packet with

the destination Mac ADDRESS field set to FF’s(broadcast) does the nic
change
it to the mac address of the system or does it send the pkt as it is.

Sends “as is”. It is sent only to the protocols which have allowed broadcast
packets in the packet filter.

the stack above accept the pkt and if an app listens for unicast pkts Rx
these pkts???

If the stack have requested the broadcast packets to be delivered to it (by
means of the packet filter) - then yes, it will receive it.

Max

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3

  1. Right now my application does not Rx the broadcast pkts that my Miniport
    sends above…How do I make the protocols above enable the broadcast
    mode???

  2. Is there a way to differentiate a unicast pkt from a multicast at the
    Miniport level???(Is it through looking at the Mac address)

  3. If I change the destination mac address(to not that of the systems Mac
    address) of my pkt and send it above my app still Rxs these pkts? Does NDIS
    not drop them???

Thanks
Daniel

-----Original Message-----
From: Maxim S. Shatskih [mailto:xxxxx@storagecraft.com]
Sent: Saturday, April 21, 2001 7:36 AM
To: NT Developers Interest List
Subject: [ntdev] Re: Unicast filtering???

I would also like to know when the NIC card receives a unicast packet with
the destination Mac ADDRESS field set to FF’s(broadcast) does the nic
change
it to the mac address of the system or does it send the pkt as it is.

Sends “as is”. It is sent only to the protocols which have allowed broadcast
packets in the packet filter.

the stack above accept the pkt and if an app listens for unicast pkts Rx
these pkts???

If the stack have requested the broadcast packets to be delivered to it (by
means of the packet filter) - then yes, it will receive it.

Max

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4

> 2. Is there a way to differentiate a unicast pkt from a multicast at the

Miniport level???(Is it through looking at the Mac address)

Yes.
The Ethernet spec says that the senior byte of the MAC address is odd for
the multicast addresses.
ETH_IS_MULTICAST macro (which checks this fact) is documented in the DDK.

Max

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