tions use class C networks. Network 192.65.175, for example, is used by a single IBM research lab. To make it easier the Internet uses names, not numbers. "For example, the machine we have heretofore referred to as 140.186.81.1 is named chico." (Levine 21) When ARPANET first came out, they had simple names; the machine at Harvard was called HARVARD. But since there are millions of names on the Net they had trouble coming up with different names. To avoid this problem they created the Domain Name System (DNS). Host names are strings of words separated with dots. For example, MILTON.IECC.COM. The part at the right of an Internet name is called a zone. In this example the part at the right is com. Com means it is a commercial site, rather than educational, military, or some other kind of zone. The next part of the name is iecc. IECC is the name of the company. The part to the left of the company name is the name of the host machine inside the company. So a computer inside of IBM could be milton: milton.iecc.com. Name zones are divided into two categories: the three-letter kind, and the four-letter kind. The three letter zones are made by organizations. Below is a table stating all the zones: Zone Meaning com Commercial organizations edu Educational institutions gov Government bodies and departments int International organizations mil Military sites net Networking organizations org Anything else that doesn't fit into any of the other categories There are also two letter zones. These zones are for national countries. Some of these zones are AU for Australia and AT for Austria. There are a few other zones. Even though the ARPANET is not in use any more, a few sites are still there for historical reasons. They have names ending in arpa. Names for some computers on the UUCP and BITNET networks, have names ending in UUCP and BITNET. These names are not real zones, but a lot of systems still route mail to them anyway. Any BITNET or UUCP site can ...
