https://en.wikipedia.org/wiki/Private_network

In IP networking, a private network is a computer network that uses private IP address space. Both the IPv4 and the IPv6 specifications define private IP address ranges. These addresses are commonly used for local area networks (LANs) in residential, office, and enterprise environments.

Private network addresses are not allocated to any specific organization. Anyone may use these addresses without approval from regional or local Internet registries. Private IP address spaces were originally defined to assist in delaying IPv4 address exhaustion. IP packets originating from or addressed to a private IP address cannot be routed through the public Internet.

The Internet Engineering Task Force (IETF) has directed the Internet Assigned Numbers Authority (IANA) to reserve the following IPv4 address ranges for private networks:

· 10.0.0.0 – 10.255.255.255

· 172.16.0.0 – 172.31.255.255

· 192.168.0.0 – 192.168.255.255

Backbone routers do not allow packets from or to internal IP addresses. That is, intranet machines, if no measures are taken, are isolated from the Internet. However, several technologies allow such machines to connect to the Internet.

· Mediation servers like IRC, Usenet, SMTP and Proxy server

· Network address translation (NAT)

· Tunneling protocol

NOTE: So, the problem is just one of these technologies.