Private network

In the Internet addressing architecture, a private network  is a network that uses private IP address space, following the standards set by RFC 1918 for Internet Protocol Version 4 (IPv4), and RFC 4193 for Internet Protocol Version 6 (IPv6). These addresses are commonly used for home, office, and enterprise local area networks (LANs). Private IP address spaces were originally defined in an effort to delay IPv4 address exhaustion, but they are also a feature of IPv6 where exhaustion is not an issue.

Addresses in the private space are not allocated to any specific organization and anyone may use these addresses without approval from a regional Internet registry. However, IP packets addressed from them cannot be transmitted through the public Internet, and so if such a private network needs to connect to the Internet, it must do so via a network address translator (NAT) gateway, or a proxy server.

Sources:
 * 1) Private network