If external IP access is required then a unique IP address space must be assigned by an Internet Registry agency, such as InterNIC.
According to RFC 1597 the following addresses are reserved for private networks and for security or other reasons they do not enable access to the internet .
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
These addresses are unique only within the intranet of the organization. Computers using IP addresses within these ranges are considered private hosts and cannot have IP connectivity to a computer that has external IP access.