Possible Duplicate:
Block TOR Servers
I would like to know if it is possible to see if a call to my PHP page is done by a TOR client (meaning the call comes in over the TOR project network). Today I call a bunch of IP adresses gotten from https://check.torproject.org/cgi-bin/TorBulkExitList.py, but it would be more fun if I can spoof the data send back to the thieves leaching my API.
I can't think of anyway to find out, is it possible? How?