The host portion of an IP address can be determined using its default subnet mask. For Class A it's the last 24 bits, for Class B the last 16 bits, and for Class C the last 8 bits. Class D addresses have no host portion as they are used for multicast.
When determining the host portion of an IP address, it is important to understand the default subnet masks for each IP class. The default subnet masks help identify which part of the IP address is reserved for the network and which part can be used for host addresses. Here's how you determine the host portion for different IP address classes:
- Class A: The default subnet mask is 255.0.0.0, indicating that the first 8 bits are for the network portion and the remaining 24 bits are for hosts.
- Class B: The default subnet mask is 255.255.0.0, which means the first 16 bits are the network portion and the last 16 bits specify hosts.
- Class C: The subnet mask is 255.255.255.0 with the first 24 bits for the network and the last 8 bits for hosts.
- For Class D IP addresses, which are used for multicast, there is no host portion because the entire address is used to identify multicast groups.
To calculate the host portion, you simply identify the bits not used by the network portion based on the default subnet mask of the specific IP class.