[Winpcap-users] While testing Gianlucas winpcap 3.1 [prerelease]...

Marc Wetzel mwse at gmx.de
Mon Aug 1 12:05:29 GMT 2005

I won't call this a bugreport, because I tried out
Gianlucas private build as you could download it from 

But maybe you are interested in my findings...

First of all I'm mainly interested in sniffing on WAN devices, as they 
where previously
exported by the Devicename \Device\NPF_GenericNdisWanAdapter
Now the devicename changed to \Device\NPF_GenericDialupAdapter.

Ok this was the easy one...

But you might remember, that I had trouble using winpcap3.1.b4/WAN 
devices with Delphi,
because of some kind of COM initialization problems.
It only worked if I do a CoInitializeEx(NIL, COINIT_MULTITHREADED) at 
the very start of the code.

With the prerelease I have now other problems...
If I use CoInitializeEx(NIL, COINIT_MULTITHREADED) I only see my 
Ethernet-Device (using pcap_findalldevs).
And if I comment the CoInitializeEx call out, I see all devices as 
expected, but then it fails
in the call to  pcap_open() with the error message "The system cannot 
find the device" (just as before).

Just an addendum:
Using CoInitializeEx(NIL, COINIT_MULTITHREADED) in a Com-Application is 
not possible,
e.g. embedding the IE-ActiveX object will always fail. This means that 
having an application which uses
both the IE-ActiveX and winpcap (sniffing on WAN devices) is not possible.

Sniffing ethernet devices is not touched by this problem.

Maybe I am completely wrong?
Does anybody have a clue, or is this a bug?


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