Direct Broadcast and restricted Broadcast

Direct Broadcast and restricted broadcast address are special IP addresses, one is direct broadcast address and the other is finite broadcast address. The direct broadcast address contains a valid network number and a host number with full "1". For example, 2018.3.30.255, 255 is a host number, and 202 is a class c ip address, class c ip addresses are common to us. The restricted broadcast address is a 32-bit full-1 IP address (255.255.255.255 ). The restricted broadcast address is 255.255.255.255.255. This address is used for the destination address of the IP datagram during host configuration. At this time, the host may not know the network mask of its network, or even its IP address. In any case, the vro does not forward a datagram whose destination address is a restricted broadcast address. Such a datagram only appears in the local network. Direct Broadcast is an address-restricted broadcast similar to 192.168.1.255/24. It is a traffic-restricted broadcast with 255.255.255.255 that can be used when the computer does not know its IP address, for example, when requesting an address from the DHCP server or when dialing PPPOE. direct Broadcast can be used in the local network or across network segments. For example, the host 192.168.1.1/30 can send a broadcast packet to 192.168.1.7 so that the host 192.168.1.5/30 can receive the packet, the premise is that the router must enable the function. in addition, no matter what broadcast, the second layer of the target MAC address is FF-FF-FF-FF-FF-FF, so that the switch can be outside the flood broadcast package. the restricted broadcast address is 255.255.255.255. This address can be broadcast in this network, and the router is not allowed to pass through it, so it is "restricted ". The direct broadcast address is the address of host number 1. For example, if the network number 192.168.1.0 subnet mask 255.255.255.0 directly broadcasts 192.168.1.255, the direct broadcast address is allowed through the vro, of course not all vrouters, by default, silly routers prevent direct broadcast. The host with the IP address 192.168.2.1 can also broadcast to the network with the IP Address 192.168.1.0.