What is the netmask for a /24 prefix length?

A /24 prefix length indicates that the first 24 bits of the subnet mask are set to 1 (representing the network part), while the remaining 8 bits are set to 0 (representing the host part). In decimal representation, this translates to 255.255.255.0.

Each octet in a subnet mask corresponds to 8 bits. For /24, the breakdown is as follows:

• The first octet (8 bits): 11111111 in binary, which equals 255 in decimal.

• The second octet (8 bits): 11111111 in binary, which equals 255 in decimal.

• The third octet (8 bits): 11111111 in binary, which equals 255 in decimal.

• The fourth octet (8 bits): 00000000 in binary, which equals 0 in decimal.

Putting this together gives the full subnet mask of 255.255.255.0. This subnet mask allows for 256 IP addresses within the subnet, of which 254 can be assigned to hosts (as one is reserved for the network address and one for the broadcast address).

Thus, the netmask for a /24 prefix length is 255.255