Which class of IP address allows a maximum of only 254 host addresses per network ID?

Class C IP addresses allow for a maximum of only 254 host addresses per network ID due to their subnet mask configuration. Specifically, a Class C address uses a default subnet mask of 255.255.255.0. This means that the first three octets (24 bits) are used for the network portion, while the last octet (8 bits) is dedicated to host addresses within that network.

With 8 bits available for host addressing, you can calculate the total number of possible addresses as 2^8, which equals 256. However, two addresses are reserved: one for the network itself and one for the broadcast address, leaving 254 usable addresses for hosts. This structure is particularly useful for small to medium-sized networks, where the number of devices requiring IP addresses typically aligns well with the 254-host limitation.

In contrast, Class A addresses are designed for extremely large networks and can accommodate over 16 million hosts. Class B addresses support about 65,000 hosts, while Class D addresses are not used for host assignments but rather for multicast groups. Therefore, Class C is the only class that fits the criteria of allowing a maximum of 254 host addresses per network ID.