smurf攻击是很简单的，它有一些IP（广播地址）地址列表，发出了一些伪造的数 据包（ICMP echo request）从而导致一场广播风暴，可以使受害主机（使它成为伪造包 的源地址）崩溃。-smurf attack is very simple. It has some IP address list and can send pseudo ICMP echo request. As a result, broadcast storm will occur.

广播和多播仅应用于UDP，它们对需将报文同时传往多个接收者的应用来说十分重要。TCP是一个面向连接的协议，它意味着分别运行于两主机（由IP地址确定）内的两进程（由端口号确定）间存在一条连接。-broadcast and multicast only used UDP. they need to be reported - the same time as the recipient of several important applications. TCP is a connection-or

根据给定的IP地址和子网掩码中1的位数，编程求出相应的广播地址和子网范围，-according to the IP address and subnet mask in which a median calculated the corresponding programming broadcast address and subnet,