i have wireshark installed and just can’t see the packets at all. When i modified the receiving section of the passthru code i could see bad ip checksum, but got that part fixed (which makes me think it isn’t a checksum problem). To test all this i have an application in the background that generates an outgoing packet every 5 seconds. When the modified passthru program is run there is NOTHING put on the network (not just a bad packet or header or something, but absolutely nothing). If I shut it down the packets are sent as normal.
In answer to your other question, I am looking exclusively for packets that are udp and on ports 34401-34403. That part of the code wasn’t in what i posted, but I am checking these header fields in the loop before comparing the device flags for a send/receive flag. I am not at my desk right now or i’d post that code if you think it would help.