A filter that determines which part of an IP address belongs to the Network ID and which belongs to the Host ID .
These levels introduce:
An IPv4 address (e.g., 192.168.1.1 ) is a 32-bit number, usually written in dotted decimal. A (e.g., 255.255.255.0 ) tells you which part of the IP is the network and which part is the host . netpractice 42 tutorial