Transcript CS 497C - Lecture 12

CS 497C – Introduction to UNIX
Lecture 39: - The Internet
Chin-Chih Chang
[email protected]
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.
The Internet Top-Level Domains
• The Internet namespace is divided into
domains and sub-domains.
• The top-level domains include the threecharacter 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.
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.
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.