These addresses can be used without fear of duplicating a unique IP address owned by another enterprise. If globally unique Internet addresses are required, contact your Internet Service Provider or the NIC (Network Information Center) at Hostmaster@NIC.DDN.MIL.
The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private networks:
Note that the first block is nothing but a single class A network number, while the second block is a set of 16 contiguous class B network numbers, and the third block is a set of 255 contiguous class C network numbers. The complete RFC 1918 can be found via FTP on nic.ddn.mil.
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255.255
For information about obtaining an RFC document, please see the following article in the Microsoft Knowledge Base:
Article ID: 142863 - Last Review: Feb 12, 2010 - Revision: 1