The following three IP address ranges are reserved for private use within the internal network of an organization. These IPv4 addresses can be used within a network, campus, and so on, and are not routable on the internet. Hence, if any packet contains any of these private IP addresses, it is dropped by the routers. Generally, the NAT mechanism is used for communicating with the public IPv4 address space when machines are working on private IPv4. The following table lists the private IPv4 address classes along with their address ranges and some special IPv4 addresses, such as link-local address and loopback address: