Figure 1 shows the Windows IPv4 Properties window with the IP address, subnet mask, and default gateway address statically configured. Figure 2 shows the dotted decimal format for the subnet mask 255.255.255.0 and the binary format below it. The octets are divided between the third and fourth octet. Figure 3 adds the IP address 192.168.10.10 above the subnet mask from Figure 2. The subnet mask is what determines which bits are network and which bits are host.