hi, Now, I have read the dhcrelay code. In my opinion, When dhcprelay receives the bootrequest from dhcpclient, it will send the packt to fallback interface. But now, the function send_fallback() used by fallback interface to send packet, can not be found. The matter puzzled me for a long time, please tell me. Thank you ! Best regards! luo_hao 2006-09-21