Subnet mask is the “all ones” bit pattern that masks the network portion of an IP address. For a Class A address, the default subnet masks is 255.0.0.0; for Class B, 255.255.0.0; for Class C, 255.255.255.0.
Subnet mask is the “all ones” bit pattern that masks the network portion of an IP address. For a Class A address, the default subnet masks is 255.0.0.0; for Class B, 255.255.0.0; for Class C, 255.255.255.0.