What You'll Be Learning About Today

• Definition of the Internet
• History of the Internet
• Demographics - Who, What, Where
• Host Names and Addresses
• Some Internet Tools
  • Telnet
  • Electronic Mail
  • FTP
  • Talk
• More Topics for This Week

• The Internet: A collection of host computers around the world that communicate across networks using a common language (protocol).
• Network: Computer equipment and cables that allow hosts to communicate with one other.
• An internet (small i): Any collection of hosts that communicate over a wide area network.
• Protocol: A specification for a manner of communication. The Internet uses TCP/IP as a Protocol.
• TCP/IP: Transmission Control Protocol / Internet Protocol. IP carries individual packets of data from one host to another. TCP makes use of IP and governs the flow of data packets. TCP also provides error checking and correction.
• Host: In general, a single computer system with its own unique name and address. Hosts can be single user or multiuser.
• Server: Any host capable of providing (serving) a service.
• Client: A host requesting a service. A host can be both a client and a server at the same time.
• Service: Any task carried out by a server on behalf of a client. Examples: File services, WWW services and printing services

• Cold war Era in the U.S. (1950s and 1960s)
• Distribution of computer resources is key.
• Computers are large and expensive.
• Shuttle data files from one site to another - cheaper than buying computers for each site.
• 1969 First network: ARPA-NET Advanced Research Projects Agency Network - Connected four computers, 3 in California and one in Utah
• 1975 ARPA-NET becomes a general purpose research network
• 1983 TCP/IP adopted as a protocol standard
• 1983 ARPA-NET and MILNET separated. Both linked together form the "Internet".
• 1990 ARPA no longer funds Internet. Privatization begins.
• Who Owns the Internet now? Phone companies, universities, schools, other companies, individuals...

Purpose: To learn who is using the Internet, what they do with it and where they live

• Currently about 9 million hosts - fairly easy to count (Source: nic.merit.edu/nsfnet/statistics/history.hosts as of 1/96)

• How many people use the Internet? Between 10 and 20 million users depending on who you believe - O'Reilly & Associates survey for example.
• Where are they from? All over the world. Large number are from the U.S. and Western Europe.
• What do they use it for? In the past, academic and military research. Recently, all forms of research (e.g., consumer) and for entertainment.
• How do they access the Internet? In the past, through universities and corporations. Recently, through private providers and major on-line services like Prodigy, Compuserve and AOL. Home PCs can now access the Internet.

Purpose: To learn how hosts on the Internet are individually identified

• Each host on the Internet has a unique Name and Address
• A name is almost always spelled in lower case letters, no spaces, with periods ("Dot") in between.
• Host names are typically broken down into 3 or 4 parts:
  1. A geographic (e.g. country) designation is given at the "highest level" for hosts outside of the U.S.:

       uk   us   ca   au   fr   it   dr   zw
     

  2. An organizational designation may be in place of geographic in the U.S. but can also appear in combinations:

     com    - A commercial company (IBM, Reebok)
     edu    - A school or University in the U.S.
     gov    - A government agency
     mil    - A branch of the military
     org    - A not-for-profit organization
     net    - An organization involved with managing
              the Internet
      

  3. The next level down is the "organizational" level. The actual name of the company, school or organization:

     rutgers    microsoft    pizzahut   planetreebok
     

  4. Within an organization, there may be several individual hosts, each with their own name:

     snoopy    cs     www    eng311pc4    pegasus
     

• These parts are assembled from right to left:

    pegasus.rutgers.edu
    andromeda.rutgers.edu
    www.microsoft.com
    lethe.leeds.ac.uk
    www.whitehouse.gov
    www.planetreebok.com
      
  

• Notice: All lower case letters with no spaces.
• Problem: Computers on the Internet can't memorize all of the possible host names.
• Each host name also has a corresponding number called the Internet Protocol Address or IP Address for short.
• This address is broken into 4 pieces separated by periods.
• Here are the IP Addresses for the hosts listed above:

  Host Name                IP Address
  --------------------     --------------
  pegasus.rutgers.edu      128.6.10.4
  andromeda.rutgers.edu    128.6.10.45
  www.microsoft.com        198.105.232.4 
  lethe.leeds.ac.uk        129.11.244.5
  www.whitehouse.gov       198.137.240.91
  www.planetreebok.com     207.19.162.14
  

• For almost all tools, one can use either the IP address or the host name. If the host name is given, the computer will look up the appropriate IP address for you.

Purpose: To learn how to log into a host using Telnet, how to compose, send and receive e-mail and how to use the File Transfer Protocol (FTP) to upload and download files

Telnet

• What is Telnet ? A program that allows you to Log in to a remote computer and to use that computer's resources.
• Whatever you type is sent over the Internet to the host. Any output is sent back over the Internet to your screen.
• This works just about anywhere in the world that has an Internet connection.
• What do I need ?
  1. The Telnet Program.
  2. The host name of a computer.
  3. A valid Username and Password for the host.
• How do I do it ?
  1. Go to the MS Windows Program Manager and double click on the PC/TCP Group to open it up.
  2. Double click on the TNVT icon. This is the Telnet Program.
  3. A dialog box will appear prompting you for a host name. Type in: cimic3.rutgers.edu
     and press Enter.
  4. After a few seconds, a welcome message will appear with a login: prompt.
  5. At the login: prompt, type in your Username and press Enter. Note: Should be all lower case letters.
  6. At the password: prompt, type in your Password and press Enter.
  7. You are now Logged in to the CIMIC 3 host.
  8. To Log out, type exit and press Enter. Note: Should be all lower case letters.

Electronic Mail

• What is Electronic Mail ? E-Mail is an electronic form of mail.
• At its most basic, e-mail allows you to send a letter or a note over a network to another person (or persons).
• E-mail can be used for much more, however - Pictures, programs, or just about any file can be sent via e-mail.
• It's Fast: Typically received in under 5 minutes
• It's Cheap: Can send e-mail to just about any user in the world.
• It's reliable (sort of): E-Mail messages rarely get lost but are not 100% guaranteed to get there.
• What do I need ?
  1. Access to an Internet host that supports E-Mail.
  2. A Mail Program.
  3. The e-mail address of someone you would like to send a message to.
• What's an E-Mail Address ? Just as each of you has a postal address, each user on the Internet has their own e-mail address.
• They are made up of two parts: Username and host name
• These are separated by an @ sign. Examples:

   Nabil Adam            adam@adam.rutgers.edu
   Barry Davis           badavis@cimic3.rutgers.edu
   Rich Holowczak        holowcza@cimic3.rutgers.edu
   Pamela Morgan         pemorgan@aol.com
   Tiffany Cunningham    tiffanyc@andromeda.rutgers.edu

• How do I do it ?
• E-Mail programs vary greatly in their use, however, the basic functions of composing a new message and reading received messages require similar fundamental steps.
• Here are notes on how to use several e-mail packages:
  • Netscape E-Mail Used on the PCs in the labs.
  • The Columbia Mail Manager (mm) used on the CIMIC 3 host.
  • The Pine E-Mail system also used on CIMIC 3.
• The following steps are for using the Pine E-Mail Program.

File Transfer Protocol - FTP

• What is the File Transfer Protocol ? FTP is a way to send files between hosts on the Internet.
• Downloading: Get a file from a remote host and save it on your computer
• Uploading: Sending a file from your computer to a remote host.
• The files can contain anything: Poetry, term papers, games, software, etc.
• FTP Differentiates between files that are binary and files that are ASCII (or text).
  • ASCII Files: ASCII or text files contain only letters of the alphabet, numbers and punctuation. Examples include HTML files and Text files (from TeachText on the Mac or Notepad in Windows).
  • Binary Files: Binary files can contain all kinds of special codes that are unreadable to us. Such files must be interpreted by specific software programs first, before we can view them. Examples of binary files are:
    Images or Pictures (.gif or .jpg)
    Word Processing Files (.doc or .wp)
    Software Programs (.exe or .com)
• What do I need ?
  1. The FTP Program.
  2. The host name of a computer.
  3. A valid Username and Password for the host.
• Well, #3 is not quite true all of the time. Anonymous FTP is a way to log in to a host and upload or download files without having a specific username and password.
• The Username given should be: anonymous and the password is typically your e-mail address.
• How do I do it ?
• As with E-Mail and News, there are many different FTP programs available.
• All of them follow these basic steps:
  1. Open a connection to a remote host by specifying the host name.
  2. Change to the appropriate directory on the remote host.
  3. Change to the appropriate directory on your PC.
  4. Choose a file format - either ASCII or Binary.
  5. Transfer the files - typically using the put and get commands or by clicking on a "Copy" button.
• Here are some specific steps for using the FTP program we have in our computer labs at Rutgers.

Function	How to Do It
Running the PC-TCP Software FTP program	In the Windows Program Manager, open up the PC-TCP Group by double clicking on it. Start up the FTP program by double clicking on the FTP icon.
Open a connection to a remote host	When the FTP program is first run, a dialog box will appear to open up a New connection. For this example, fill in the information as follows: Host name: cimic3.rutgers.edu Username: Your user name for the CIMIC 3 host. Password: Your password for the CIMIC 3 host. After filling in these three fields, click on the "Connect" button.
Change directories	The main screen of the program is divided into two halves. On the left is a listing of files for the PC you are using and on the right is a listing of files for the remote host. Use the scroll bars to scroll down the file lists. For the PC side, scroll all the way to the bottom to see the different drive letters. e.g., the "A:" or "B:" drives are the floppy drives.
Uploading and Downloading files	To upload a file from your floppy disk to the CIMIC 3 host, use the scroll bars on the PC side to change the directory to your floppy disk. Highlight a file to upload by clicking on the file name one time. Choose the appropriate file type - either ASCII or Binary. Click on the "Copy" button to transfer the files. To download a file from CIMIC 3 to your floppy disk, highlight the files in the right side window. Note the arrows around the "Copy" button will change direction. Click on the copy button to transfer the files.

Talk

• What is the Talk Program ? The talk program allows you to type messages to a friend in "real time" - as you type, your friend sees it on their screen and vice versa.
• An improvement over e-mail because the response is instant.
• Not as convenient because you both need to be logged in.
• What do I need ?
  1. The Talk Program.
  2. An account on a host.
  3. The username of the person you'd like to "talk" to.
• How do I do it ?
  1. Make sure you're logged in to CIMIC 3 as described in the Telnet section above.
  2. Get the username of your neighbor.
  3. Type: talk username where username is the username of your neighbor.
  4. Your neighbor will see something like the following:

Message from Talk_Daemon@cimic3.rutgers.edu at 11:17 ...
talk: connection requested by holowcza@cimic3.rutgers.edu.
talk: respond with:  talk holowcza@cimic3.rutgers.edu

• To complete the connection, your neighbor types: talk username
• What you type will be on one half of the screen, what your neighbor types will be on the other half.
• To end the conversation, press ^C (hold down the control key and press the letter "C").

• The World Wide Web (WWW)
• Using the Netscape WWW Browser
• WWW Search Engines
• More Netscape Features
• Building your own WWW Pages