Subnetwork Rule matches an IPv4 address based on its belonging to the specified IPv4 subnet. Subnetwork is defined by specifying an IPv4 address and an IPv4 netmask.

Examples:

• Address 192.168.0.0, Subnet Mask 255.255.255.0 (192.168.0.0/24): matches addresses in range from 192.168.0.0 to 192.168.0.255
• Address 10.0.0.0, Subnet Mask 255.0.0.0 (10.0.0.0/8): matches addresses in range from 10.0.0.0 to 10.255.255.255
• Address 172.16.0.0, Subnet Mask 255.240.0.0 (172.16.0.0/12): matches addresses in range from 172.16.0.0 to 172.31.255.255