Incorrect NDIS Filtering of Some Ethernet Multicast Frames (216303)

SYMPTOMS

Some Ethernet multicast frames may be incorrectly identified as Ethernet broadcast frames by the filtering logic in Ndis.sys.

Consequently, these multicast frames are not always delivered as expected to NDIS packet drivers and higher layers of the network stack.

CAUSE

Ethernet multicast frames are distinguished from directed packets by having the Individual/Group (I/G) bit of the destination address set to 1 (Group).

The Ethernet broadcast address is defined to be 0xFFFFFFFFFFFF, which is a special case of Ethernet multicast address.

Frames with an Ethernet multicast destination address whose first byte was 0xFF were being incorrectly identified and treated as broadcast frames.

WORKAROUND

To work around this problem, choose an Ethernet multicast addressing scheme that does not include Ethernet multicast addresses whose first byte is 0xFF.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to:

http://www.microsoft.com/windows/servicepacks/ -or-
152734 how to obtain the latest windows nt 4.0 service pack

For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://support.microsoft.com/directory/overview.asp

STATUS

Microsoft has confirmed that this is a problem in Windows NT 4.0. This problem was first corrected in Windows NT version 4.0 Service Pack 5.