I would like to configure the computers in my private network so they would not be unintentionally connected to other networks. My thought was to reconfigure the DHCP discover packet in the client from a broadcast of 255.255.255.255 to 10.255.255.255. If the DHCP server ignored the discover requests then the errant computer could not connect and they would call the company help desk. I know this is not a strong solution for preventing company computers from connecting to other networks, but it would have prevented all of the accidental connections to other networks that I have seen so far. This is assuming that changing the DHCP request wasn't too labor intensive.