[Winpcap-users] winpcap captures packet,
but winsock doesn't see it
coleman.brumley at jandasoft.biz
Wed Jan 7 19:45:18 GMT 2009
Thank you for your response.
It turns out it was a software firewall issue. Very strange since the
firewall claimed to "block UDP broadcasts", but *only* blocked them on the
255.255.192.0 subnet. If we changed the mask to 255.255.255.0, then it
wasn't being blocked.
> -----Original Message-----
> From: Gianluca Varenni [mailto:gianluca.varenni at cacetech.com]
> Sent: Wednesday, January 07, 2009 2:42 PM
> To: coleman.brumley at jandasoft.biz; winpcap-users at winpcap.org
> Subject: Re: [Winpcap-users] winpcap captures packet, but winsock
> doesn't see it
> It's definitely not a NIC issue. The TCP/IP protocol driver is
> that packet for some reason that doesn't come to my mind at the moment.
> What is the MAC src and destination addresses that you are using?
> ----- Original Message -----
> From: "Coleman Brumley" <coleman.brumley at jandasoft.biz>
> To: <winpcap-users at winpcap.org>
> Sent: Tuesday, January 06, 2009 1:47 PM
> Subject: [Winpcap-users] winpcap captures packet, but winsock doesn't
> see it
> > Hello all.
> > I have a strange problem and I was hoping someone could point me in
> > right direction.
> > I have an issue where 2 IP endpoints are configured as 18.104.22.168
> > 22.214.171.124 with subnet masks of 255.255.192.0. They are connected
> via a
> > switch. I'm not sure of the switch manufacturer.
> > Device A (a WinXP PC running a Winsock application) sends a UDP
> > to
> > 126.96.36.199. Device B (an embedded device) replies to that
> > with
> > another broadcast to 188.8.131.52. Wireshark/Winpcap is running on
> > PC.
> > Wireshark captures the reply, but the reply doesn't get to the
> Winsock app
> > running on Device A. It's like the app just never received the
> > (i.e.
> > recvfrom doesn't indicate that any data has been received).
> > I'm unable to duplicate this behavior in my similar environment, so
> > something tells me it's the PC in question or some other hardware
> > (something with the NIC driver?).
> > Regards,
> > Coleman
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