Broadcast address

At the data link layer on Ethernet networks, it is a specific MAC address.

[3] The directed broadcast address for any IPv4 host can be obtained by taking the bit complement (bitwise NOT) of the subnet mask and then performing a bitwise OR operation with the host's IP address.

Directed broadcasts always work within a subnet but, for security reasons, many routers disable the forwarding of these by default.

[5][6] IP broadcasts are used by BOOTP and DHCP clients to find and send requests to their respective servers.

Broadcast is possible also on the underlying data link layer in Ethernet networks.

When the node number is specified as FFFFFFFFFFFF, the packet is intended to be received by all hosts in the network.