[Winpcap-users] error while building winpcap

Guy Harris guy at alum.mit.edu
Thu Nov 20 19:59:03 GMT 2008

On Nov 20, 2008, at 10:55 AM, Joshua (Shiwei) Zhao wrote:

>> How do you configure your WiFi driver to go into promiscuous mode?  
>> Is it
>> done through the usual
>> OID_GEN_CURRENT_PACKET_FILTER, a custom OID code or some other  
>> mechanism?
> We know from the manufacturer how to set their driver to that mode.

So what is "that mode"?

Note that, at least as I understand it, some if not all wireless  
adapters support a promiscuous mode that's similar to Ethernet  
promiscuous mode, in that the adapter is associated with a network,  
and drops packets for other networks, but *does* provide to the host  
packets that aren't unicasts to the adapter, broadcasts, or multicasts  
to a multicast address for which the adapter is accepting packets.

If so, then a Windows adapter for that driver should, if it's told to  


should put the adapter into promiscuous mode - *that's* how the driver  
should be put in that mode.

If the driver supports that, *no* changes to WinPcap are necessary to  
support it.

If the driver requires anything else to put it into that mode, the  
driver isn't a good NDIS driver, and should be fixed.

Now, wireless adapters might also support "monitor mode", which is not  
the same thing as promiscuous mode.  In monitor mode, the adapter will  
provide to the host all packets it receives, regardless of what  
network they're on.

If *that's* what you mean, WinPcap doesn't currently support that.   
Prior to Vista, Windows NDIS didn't support monitor mode; in Vista,  
with NDIS 6.0 it supports it:


Note that Microsoft seem to indicate that promiscuous mode should be  
supported only when in monitor mode:


and, apparently, in monitor mode, a driver must not send packets, so  
you can't be on a network and run in promiscuous mode.

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