It seems like people are mainly reporting problems here. Let me report some success.
My company is making battery testers and the tester HW has some 188 microcontrollers which are communicating with the PC program over a standard LAN cable and net adapter by "raw packets". In the past the NE2000 was state of the arts and PC-code was developed to talk to directly to NE2000 compatible chips. First version was written in assembler, then my predecessor started to rewrite it in PowerBasic which I completed and then once again I converted it to Delphi. All together it has been working very successfully and all our equipment is based on this inexpensive and reliable communication. However, NE2000 adapter are 10MBit only and normally bound to the ISA slot - all getting rapidly obsolete, so something had to be done. We have been considering conversion boxes so we could let the PC "speak" UDP (our protocol happens to be rather similar to UDP with a simpler header) and let the controller board code as it is, but it would have been an expensive, slow and complicated solution to something that obviously should be done in SW. So in a last minute internet search before the kick off meeting of the conversion box, I ran into the WinPCap that came as sent from heaven. With a little help from Loris - thanks a LOT! - and after getting a couple of bugs fixed it works very well. The main application is written in VB6 (yak!) but the LAN stuff was already in a Delphi DLL, then I found some Delphi wrappers for the PacketDLL and it is now all bundled up and works remarkably well. In fact it is a little faster than the original very simple direct chip communication in some cases. And most important: It works with any net adapter that windows will know of on any windows from 98 to XP. Thanks for a brilliant job - I wish you all the best! Jens Munk.
