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back slash (/). For example, a typical Class C address could be written as
192.168.234.245/24, which means that the net mask is 24 ones followed by 8 zeros.
(11111111 11111111 11111111 00000000).
D.1.1.2 Subnet Addressing
Subnet addressing enables the split of one IP network address into multiple physical
networks. These smaller networks are called subnetworks, and these subnetworks
can make efficient use of each address when compared to needing a different
network number at each end of a routed link. This technique is especially useful in
smaller network environments, such as small office LANs.
A Class B address provides 16 bits of node numbers, which enable 65,536 nodes.
Since most organizations don’t require such a large number of nodes, the free bits
can be reassigned with subnet addressing.
Multiple Class C addresses can be made from a Class B address. For example, the IP
address of 172.20.0.0 allows eight extra bits to use as a subnet address, since node
addresses are limited to a maximum of 255. The IP address of 172.20.52.212 would
be read as IP network address 172.20, subnet number 52, and node number 212.
Besides extending the number of available addresses, this technique also allows a
network manager to design an address scheme for the network by using different
subnets. This can be useful when trying to distinguish other geographical locations
in the network or other departments in the organization.
D.1.1.3 Private IP Addresses
When isolated from the Internet, the hosts on your local network may be assigned
IP addresses with no conflicts. However, the Internet Assigned Numbers Authority
(IANA) has reserved several blocks of IP addresses for private networks. These
include:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.16.255.255
192.168.0.0 - 192.168.255.255
When assigning IP addresses to your private network, be sure to use IP addresses