How to receive broadcasts under Windows 7.

• Thursday, November 15, 2012 8:02 AM

   

   
  

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  I have a DSP connected to a Windows 7 laptop by Ethernet. The laptop has all firewalls disabled

  The DSP is sending well-formed BOOTP broadcast packets every three seconds to port 67 on a dedicated Ethernet connection (no routers in the way). Wireshark running on the laptop sees these BOOTP packets coming in. (destination MAC = FF-FF-FF-FF-FF-FF, source & destination IP addresses are 0.0.0.0 - this cannot be changed).

  I have a program running on the laptop with a socket successfully bound to port 67 (with s_addr=INADDR_ANY). I can see this using CurrPorts. Nothing else is shown as accessing port 67.

  The program never sees any packets coming in.

  If I run a program in the DSP that sends UDP packets to port 67 but with the Windows 7 machine's MAC address as destination, Wireshark sees them coming in and reports that they are corrupt BOOTP packets, but now, my program gets them.

  I have also tried a different program in the DSP sending the same packets but to port 0xC0C0 in case it was a port 67 issue; these also fail to get through to a program correspondingly modified.

  Any idea what’s going on here and how can I read the broadcast packets?

  
  I can post the code if necessary but will wait until asked.
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