Freecom NETWORK HARD DRIVE PRO User Manual page 81

Appendix
The IP address shortage
GB
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 addresses
to cover any need. Theoretically, you could have 4,294,967,296 unique addresses. 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 ad-
dresses 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.
DHCP
First, most users today have a dynamically given IP address or DHCP address from their
provider. This means that the IP address given to you can change over time. This allows
the provider to use the IP address for more then one person or device, since people are
often online at different times. Optimal usage of IP addresses is guaranteed.
Your Network Drive Pro gives its internal addresses to your computers in the same way.
For the DNS (Domain Name System) it is difficult to translate your domain name "www.
yourname.sharemydisk.com" to your IP address if your IP address keeps changing.
The system needs to be updated each time your IP address changes. Hence Dynamic
DNS (DDNS) programs. These programs check the latest IP address and update the DNS
system accordingly.
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