如果要在Win2000下实现类似Ping BackDoor for Linux的后门，必须以 sniffer 的方式监听ICMP包，而在win2000下写一个简单的sniffer-If you want to Win2000 achieve Ping BackDoor for Linux similar to the back door, you must listen ICMP packet sniffer manner, but in the next win2000 write a simple sniffer