1. CS 497C – Introduction to UNIX Lecture 39: - The Internet Chin-Chih Chang chang@cs.twsu.edu chang@cs.twsu.edu

2. The Internet The Internet is the unintended outcome of research by ARPA (Advanced Research Projects Agency) of the United States Defense Department to develop a reliable computer-based communications system. The net is a collection of networks running on TCP/IP. Apart from ftp and telnet. The Internet also offers mailing lists, news group, the Internet Relay Chat and the World Wide Web.

3. The Internet Top-Level Domains The Internet namespace is divided into domains and sub-domains. The top-level domains include the three- character generic domain names like com, net, edu and org. All countries including the United States have two-character top-level domain names. The authority to create sub-domains is delegated to the local authorities.

4. Mailing Lists A mailing list is handled by a program to reflect a message automatically to members of a list. The request for subscription and other information is addressed to the administrator, while the message itself is addressed to the list address. Newsgroups serve news using the Network Transfer Protocol (NNTP) at port 119.

5. Newsgroups You have to subscribe to a newsgroup, which uses a hierarchical naming scheme similar to that used by domains. A newsreader fetches the headers first, and only the selected contents are downloaded. Tin is a versatile character-based news reader, but you can also use Netscape for handling news. Many more services available on the Internet are waiting for your exploration.