How do you determine the broadcast address for a given IPv4 subnet?

• A. Set all host bits to 1 within the subnet; e.g., 192.168.1.0/24 broadcast is 192.168.1.255.
• B. Set the network address to all ones.
• C. Use the gateway address as the broadcast.
• D. Broadcast address is always the highest address in the private range.

Answer: (A)

In IPv4 subnetting, the broadcast address is formed by setting all host bits to 1 within the subnet. The network address uses all host bits as 0, so the broadcast is the last address in that subnet range. You can think of it as the result of OR-ing the network address with the host mask (the part of the address that varies for hosts).

For example, with 192.168.1.0/24, the network portion is 192.168.1 and the host portion is the last octet. Setting the host bits to 1 gives 192.168.1.255. This broadcast address is used to send a message to all devices in that subnet. It isn’t the gateway address, and it isn’t determined by private-range rules—it's defined by the subnet mask.