ZyXEL Communications 128L user manual IP Addresses and the Internet

IP Addresses and the Internet

Conventionally, the Internet (with a capital I) refers the large-scale interconnected networks across the world that was originally developed by the US Department of Defense. The Internet uses exclusively the TCP/IP suite of protocols. The term “internet” (lower case i), however, refers to any interconnected networks using any protocol. An internet can be as simple as two hosts on a LAN, or it can be as complex as the Internet itself.

Every machine on the Internet must have a unique address within that internet. If your networks are isolated from the Internet, e.g., only between your two branch offices, you can assign any IP addresses to the hosts without problems. However, the Internet Assigned Numbers Authority (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

For this reason, it is recommended that you choose your network number from the above list.

You can obtain your IP address from the IANA, from an ISP, or assigned from a private network. If you belong to a small organization and your Internet access is through an ISP, the ISP can provide you with the Internet addresses for your local networks. On the other hand, if you are part of a much larger organization, you should consult your network administrator for the appropriate IP addresses.

ONOTE: REGARDLESS OF YOUR PARTICULAR SITUATION , DO NOT CREATE AN ARBITRARY IP ADDRESS; ALWAYS FOLLOW THE GUIDELINES ABOVE. FOR MORE INFORMATION ON ADDRESS ASSIGNMENT, REFER TO RFC 1597, ADDRESS

32 Configuring for Internet Access