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Appendix
If your local network is not connected to the Internet (for example, when using NAT), you
can assign any IP addresses to your computers without problems. But to prevent
problems and ease configuration, the IANA has reserved the following three blocks of IP
addresses specifically 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
We recommend that you choose your private network number from this range. The
DHCP server of the FSG is preconfigured to automatically assign private addresses.
For more information about address assignment, refer to RFC 1597, Address Allocation
for Private Internets, and RFC 1466, Guidelines for Management of IP Address Space. The
Internet Engineering Task Force (IETF) publishes RFCs on its Web site at www.ietf.org.
The IP address shortage
The Internet has grown larger than anyone ever imagined it could be. Although the exact
size is unknown, the current estimate is that there are about 100 million hosts and more
than 350 million users actively on the Internet. In fact, the rate of growth has been such
that the Internet is effectively doubling in size each year.
When IP addressing first came out, everyone thought that there were plenty of ad-
dresses to cover any need. Theoretically, you could have 4,294,967,296 unique ad-
dresses. The actual number of available addresses is smaller (somewhere between 3.2
and 3.3 billion) because of the way that the addresses are separated into classes, and
because some addresses are set aside for multicasting, testing or other special uses.
With the explosion of the Internet and the increase in home networks and business
networks, the number of available IP addresses is simply not enough. The obvious
solution is to redesign the address format to allow for more possible addresses. This is
being developed (called IPv6), but will take many years to implement because it requires
modification of the entire infrastructure of the Internet.
There are 2 systems in place now to help bring down the shortage of IP addresses.