In a net mask address, how are the network and host portions identified?

In a net mask address, the network and host portions are identified through the use of binary representation where a mask distinguishes which part of the address refers to the network and which part refers to the host.

The correct answer states that the network portion is set to all ones, and the host portion is set to all zeros. This is the standard method of defining a subnet mask. In binary format, the ones represent the bits that are used to identify the network, while the zeros represent the bits that are used to identify the individual hosts within that network.

For example, in a subnet mask of 255.255.255.0 (or /24 in CIDR notation), the first 24 bits are ones (network portion), and the last 8 bits are zeros (host portion). This allows for 256 possible addresses within that network, with the first address typically reserved as the network address and the last address as the broadcast address, leaving 254 usable addresses for hosts.

This method of differentiation is crucial for routing data through networks, as it allows devices to determine whether an IP address falls within their local network or if the traffic needs to be forwarded to another network.

The other options do not adhere to the correct representation of a subnet mask