Definition of no ip directed-broadcast configuration under the interface

About the meaning of no ip directed-broadcast configuration under the interface, we often see a command under the Cisco device interface configuration: no ip directed-broadcast, but many people do not know the meaning of this command, I checked the information and gave a rough explanation. I hope you can understand it. Generally, the www.2cto.com Router does not forward the full broadcast package of 255.255.255.255, but forwards the broadcast package with the host space of 1 by default, for example, 192.168.1.255/24, that is to say, when we need to test the host accessibility of a CIDR block, we can ping the broadcast address of the CIDR block. In this way, all IP addresses in the CIDR block will reply to the echo packet to ping the test host. However, if someone wants to maliciously attack this CIDR Block, they can directly use the directed-broadcast feature of the router ip address to launch attacks easily. Www.2cto.com therefore, for security reasons, we usually configure no ip directed-broadcast on the interface to prevent malicious network attacks. Ip directed-broadcast allows forwarding of broadcast packets with the host bit of all 1. no ip directed-broadcast prohibits forwarding of broadcast packets with the host bit of all 1.