敌人发送ICMP类型17地址掩码请求收集信息对目标网络的配置。ICMP请求地址掩码是由rfc - 950,“互联网标准的子网划分程序。”An Address Mask Request is an ICMP type 17 message that triggers a remote system to respond with a list of its related subnets, as well as its default gateway and broadcast address via an ICMP type 18 Address Mask Reply datagram. Gathering this type of information helps the adversary plan router-based attacks as well as denial-of-service attacks against the broadcast address.