A Beginner's Guide to the Internet/INTERNET.ISO/text/guides/info/whatis_i.faq

Text File | 1996-05-06 | 12.6 KB | 273 lines

What is the Internet?

by Paul Jones
Office for Information Technology
University of North Carolina
Chapel Hill, NC
([e-mail])

Permission to reprint and distribute given only if this attribution is
also given.


   "In the beginning there was the ARPAnet, a wide area experimental
network connecting hosts and terminal servers together.   Procedures
were set up to regulate the allocation of addresses and to create
voluntary standards for the network.  As local area networks became
more pervasive, many hosts became gateways to local networks.  A network
layer to allow the interoperation of these networks was developed and
called IP (Internet  Protocol).  Over time other groups created long
haul IP based networks (NASA, NSF, states...).  These nets, too,
inter-operate because of IP.  The collection of all of these
interoperating networks is the Internet. "

     So begins The Hitchhiker's Guide to the Internet, a text prepared
in 1987 by Ed Krol. Since those ARPAnet days, the Internet has grown
and divided without losing interoperability, allowing researchers,
scholars, students, and even introverted computer nerds to interact
with thousands of their peers around the world.  As of August 1989,
there were over 118,000 sites (computers) directly connected to the
Internet. Each site has from 2 or 3 to several thousand people using
the computer at that site. Thus the Internet has a population size
close to that of a major city.  The resources of this city include
some of the world's fastest super-computers, some of the world's most
sophisticated computer software (which is often shared), library card
catalogues of many major universities, and often intelligent discussions
with experts (accredited and self-proclaimed) on every subject under the sun.

     The major means by which this "massive information highway" serves
its participants is by the support of the three "canonnical" applications:
electronic mail (mail), file transfer (ftp), and remote login (telnet).
These applications will be briefly covered in this document along with
a few suggestions for you to try out.

Mail (aka SMTP)

     Mail, often called SMTP or Simple Mail Transfer Protocol, is probably
the most used Internet service. While the mail interface (what you see when
you type mail on your computer) may be different on each computer (see your
local support folks for details), the means by which Internet computers
deliver mail is standardized, as is the way by which you address other
people on the Internet.

     Unlike certain other networks with which you may be familiar (UUCP
and BITNET), Internet mail is either delivered directly to the recipient
or sent through a small number of gateways which are usually hidden from
the person originating the message.  Under this scheme, mail is much
less often held up due to a computer being "down" somewhere between you
and your correspondent. Of course, telephone and other communication
lines could still be a source of delay, but in general SMTP mail is
delivered much faster.

     [e-mail] is my mail address. Let's look at how
it is composed.

     pjones     my user logon id
     @             separates the user from his address
     samba      my computer's name (ours are named after lively dances)
     oit     my department  (Office FOR Information Technology)
     unc        my organization (University of North Carolina)
     edu        Internet domain (edu for educational institutions)

     Other Internet domains are:
    com    commercial operations
    gov     government agency
    mil    military sites
    net    network centers
    org     organizations that fall between the cracks

When you think of it, the address is a lot like an address on a
letter, moving from most specific to most general.  That's how
postal systems delivering paper mail worldwide work and how the
Internet works, too.

     Ocasionally you may need to use "gateway addressing" in order
to reach people on networks other than the Internet. To reach BITNET
sites, you may send to [e-mail] or you may need to specify
a gateway (if your systems folks are new or lazy) by sending to
[e-mail]. In general, most sites hide
gatewaying from their users and make your life easier.

     All major networks can send and receive mail from the Internet
so you need not fear losing communication with your friends on the
other nets by using Internet mail.


Logging on to other computers on the Internet (telnet and tn3270)

    You may be working with people at another site, you might want to
use a database in another state, you might need the power of a super-
computer to assist you in your research, or you might want to browse
a library card catalogue at another institution. You can do all this
on the Internet without the expense of a long distance telephone call.

    telnet, also known as remote virtual terminal, allows you to log on
to computers on the Internet by using the same form of address you saw
above in the Mail section. telnet can emulate any terminal type that
you can emulate locally, but it is most often a vt100 emulation or a
Tektronics 40xx emulation for graphics. If you want to log on to an
IBM computer running the VM or MVS operating system, you'll need a
special version of telnet called tn3270 which emulates an IBM full
screen 3270 terminal.

To connect to the UNC ACS bulletin board system, you'd type:
             telnet samba.oit.unc.edu
      then login: bbs and follow the instructions for using bbs.

      Notice that the samba.oit.unc.edu is the same computer you saw
in my mail address; the information to the right of the @ is the
computer's name.  However, Internet connections may also be made by
using an IP address instead of a name. The IP address is a group of
four numbers separated by periods. If your computer does not run the
Internet name service program, you will need to use IP addressing for
telnet and ftp.

To connect to samba.oit.unc.edu by IP address, you'd type:
     telnet 128.109.157.30

To connect to the University of California's Library Service, you'd type:
    telnet melvyl.ucop.edu
To connect by IP address, you'd type:
     telnet 31.1.0.11
From there you'll be given local prompts to help you use the MELVYL system.

      Another service you may reach via telnet is VideoText. By typing
telnet uncvx1.oit.unc.edu ( or by IP address, telnet 128.109.157.1)
and logging on as info, you may access the University of North Carolina's
info video text system, a system that will allow you to locate faculty,
staff and students at UNC Chapel Hill, to check for job openings, and to
review the campus calendar.  (As I write this you must emulate a vt100
in order to make full use of info).


Moving data on the Internet  (ftp)

      Suppose you have a document on another computer and you need to
have it on the computer you're now using. You may use the resources of
the Internet for very high speed file transfer to copy that document
from the other computer to the computer you are using now--even if the
computers are on different continents--without the expense of a telephone
call. Authorized folks may access files on any computer that allows such
file access, but only if the owner of the files gives permission to access
them. There is much information on the network that is open to the public.
ftp, file transfer protocol, uses a subset of UNIX commands to allow you
to change file directories - cd; list a directory's members - ls;
show your current directory - pwd; as well as retrieve - get and send - put
files. You may use the help command to learn more about other ftp commands.

      There is a special user id used on the Internet called anonymous.
This is used to make certain files available to everyone on the Internet.
We use anonymous ftp at UNC to make documentation and support files
available to people on our campus, but we welcome others on the Internet
to use them, too.

      Here is a sample ftp session in which a file called library.guide
(a guide to library card catalogues accessible on the Internet is
retrieved from samba.oit.unc.edu.  You would type the commands that
follow the ftp> prompt after initiating a session by using the ftp
command. (Remember you could use the IP address of 128.109.157.30
instead of samba.oit.unc.edu.):
      ftp samba.oit.unc.edu
Connected to samba.oit.unc.edu.
220 samba.oit.unc.edu FTP server (Ultrix Version 4.36 Thu Dec 29 22:53:11 EST 1988) ready.
Name (samba.oit.unc.edu:pjones): anonymous
331 Guest login ok, send ident as password.
Password:type your id here--it will be hidden
230 Guest login ok, access restrictions apply.
ftp> ls
200 PORT command successful.
150 Opening data connection for /bin/ls (128.109.157.70,4260) (0 bytes).
bin
pub
uploads
226 Transfer complete.
36 bytes received in 0.23 seconds (0.15 Kbytes/s)
ftp> cd pub
250 CWD command successful.
ftp> ls
200 PORT command successful.
150 Opening data connection for /bin/ls (128.109.157.70,4261) (0 bytes).
docs
msdos
unix
vms
226 Transfer complete.
103 bytes received in 0.21 seconds (0.48 Kbytes/s)
ftp> cd docs
250 CWD command successful.
ftp> ls
200 PORT command successful.
150 Opening data connection for /bin/ls (128.109.157.70,4262) (0 bytes).
hitch.hiker
library.guide
other.anonymice
tcpip.intro
226 Transfer complete.
188 bytes received in 0.11 seconds (1.64 Kbytes/s)
ftp> get library.guide
200 PORT command successful.
150 Opening data connection for library.guide (128.109.157.70,4263) (45172 bytes).
226 Transfer complete.
local: library.guide remote: library.guide
46571 bytes received in 0.66 seconds (69.02 Kbytes/s)
ftp> quit

     The file other.anonymice contains a list of over 200 sites that make
software and documents available to people on the Internet.

Select Bibliography

* indicates that these documents are available via anonymous ftp from
samba.oit.unc.edu or nic.ddn.mil

Comer, Douglas. Internetworking with TCP/IP. Prentice Hall, Englewood Cliffs,
NJ: 1988. Used to teach networking by our CS department. Technical view of the
underlying protocols.
UPDATE: now in two volumes, this book now deals more deeply with newer expanded
network operation.

Frey, Donnalyn and Rick Adams. !%@:: A Directory of Electronic Mail Addressing
and Networks. O'Rielly and Associates, Inc. Sebastopol, CA: 1989
([e-mail]). Cheap and good. About two pages with maps covering the
world for each of over 130 networks.
JAN 1992 UPDATE: much expanded after 2 editions. now includes a handy pocket
guide (although I can't see that much use for it).

Goos, Anke and Daniel Karrenberg. The European R&D E-Mail Directory. European
Unix Systems User Group, Buntington, Herts, United Kingdom: 1989.
([e-mail] or [e-mail]). Every campus user service should
have this. A sort of yellow (they are actually green) pages of European
addresses and postmasters with a very good introduction. Should be a newer
version available than this one.  Not cheap in the States.

*Hedrick, Charles. Introduction to Internet Protocols (tcpip.intro on samba)
Great brief technical overview.

*Krol,  Ed. Hitichhiker's Guide to the Internet (hitch.hiker on samba) once
you've tried out some of the suggestions in this document get this one.

LaQuey, Tracy. Users Directory of Computer Networks. Digital Press,
Bedford, MA: 1990. Comprehensive and a good companion to Quarterman,
but many of these lists of networks and hosts would be much more useful
if available over the net so they could be searched electronically
instead of printed on the bodies of dead trees.

*NSF Network Service Center. Internet Resource Guide (in resource.guide
directory) In both postscript and plain test format. This is the official
guide and so lags behind the unoffical guides to libraries and super-
computers, but trustworthy.

Quarterman, John. The Matrix: Computer Networks and Conferencing Systems
Worldwide. Digital Press, Bedford, MA: 1990. ([e-mail]).
The Bible. Every campus should be required to have this.

Todino, Grace and Dale Dougherty. Using UUCP and Usenet. O'Reilly and
Associates, Inc. Sebastopol, CA: 1989 ([e-mail] ) Handy guide for
Unix folks, but not all that much to do with the Internet or the coming NREN.

Waite Group. UNIX Communications. Howard W. Sams & Company, Indianapolis:
1987. Great users guide to various Unix network applications.


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