What IP address is used for sending broadcast requests on a network?

To send broadcast requests in IPv4 networks, an IP address with the last octet filled with ones is used, for example, 255.255.255.255 — this is a global broadcast address that addresses all devices in the local network. A address with the last octet 255 is also commonly used, for example, 192.168.1.255 for the 192.168.1.0/24 network.

Example: if your network is 192.168.1.0 with a mask of 255.255.255.0, then the broadcast address will be 192.168.1.255. Sending a packet to this address reaches all devices in this subnet.