What does the host address consisting of all ones signify?

• A. All hosts on the specified network
• B. The network address
• C. The subnet mask
• D. The default gateway

Answer: (A)

A host address with all host bits set to one is the broadcast address for that subnet. In IPv4, the network portion is defined by the subnet mask, and the remaining bits are the host portion. When every host bit is one, the address is reserved to reach every device on that local network, so a message sent to it is delivered to all hosts on the subnet. It isn’t the network address (which uses all zeros in the host portion), it isn’t the subnet mask (that defines which bits belong to the network versus hosts), and it isn’t a default gateway (which is a particular router IP within the network).