TELECOMMUNICATIONS AND THE INTERNET Jonathan Davis, Network Support Manager Brenda Smith, Computing Applications Specialist Eugene Simpson, Economist and Computer Coordinator Introduction ACES staff now have full access to an international set of interconnected computer networks loosely referred to as the Internet. This network encompasses the ARPAnet (Advanced Research Projects Agency), NSFnet (National Science Foundation), MILnet (U.S. Military), SURAnet (all U.S. Supercomputers), and thousands of regional, corporate, and University networks found in the international computing community. All of these different networks are connected over high-speed lines by gateways, and use industry standard TCP/IP (Transmission Control Program/Internet Protocol) to transparently communicate with each other. The primary standard Internet features are remote login (telnet), file transfer (ftp), and mail (SMTP). Several additional features are also supported, such as Network News Transfer Protocol (NNTP). More features and services are being added to the Internet constantly, and existing ones are being improved. One of the best and most important features of the Internet is that it is FREE to users, since all of the costs are incurred by the supporting agencies! Internet Addresses Every local area network host computer (server) has a unique Internet address assigned. All client stations (terminals, workstations, and PC's which are directly connected with a network interface card to the local server) also have a unique Internet address. These addresses are of the form ###.###.###.###. The unique Internet address for the ACENET server in Duncan Hall is 131.204.46.253, and every PC and workstation in Duncan Hall, Extension Hall, and Duncan Annex has an address of 131.204.46.###. Users in the following buildings have similar addresses: Comer Hall 131.204.52.###, Spidle Hall 131.204.57.###, Swingle Hall 131.204.37.###, ADS Building 131.204.49.###, Ag Engineering Building 131.204.18.###, Forestry Building 131.204.43.###, and the Agronomy Department 131.204.60.###. Since numerical addresses are so difficult to deal with, a feature called Domain Name Service is used which matches the numerical address with a domain name. Thus, a user's userid combined with the domain name provides a unique address. ACENET users have the following address: userid@acenet.auburn.edu where userid is your ACENET id, such as athompso, esimpson, etc. All ACENET users have this same address even if they are housed in a different building. Using combinations of userids, domain names, and filenames can allow you to specifically target any individual, server, database or mailing group located anywhere on the Internet. Each Telecommunications & Internet domain name has a 2 or 3 character suffix appended which denotes the type or organization or entity the domain represents. Educational institutions are .edu, government is .gov, military is .mil, and commercial companies are .com. Other countries generally use a 2 letter designation such as .ca for Canada, .dk for Denmark, and .au for Australia. Remote Login Remote login (telnet) is a powerful feature which enables users to connect to hosts (servers) locally, across campus, in other states, and in other countries. Without this capability, users would have to resort to using modems and telephone lines to make these connections - a process that is unreliable, slow, and expensive. To connect to another host simply login to ACENET, at the MAINMENU select the "UNIX Operating System" option, and type the following: telnet host where host is the domain name (or Internet address, if you prefer) of the remote system. Examples are: telnet ducvax.auburn.edu telnet npirs.purdue.edu telnet hubcap.clemson.edu telnet 131.204.46.10 Naturally, in order to connect to another host you will more than likely need a userid and password. These are usually assigned by the host's system administrator. If you are using a graphics oriented workstation (such as a Sun SPARCstation) you may preserve your local graphical environment by substituting "rlogin" for "telnet". Selected telnet commands are listed at the end of this document. File Transfer File Transfer (ftp) provides you with the ability to send and receive data and program files to and from remote hosts. By using ftp, a 10 Megabyte file can be transferred from a remote host to ACENET in less than 20 seconds. Many host systems allow "anonymous ftp", the ability to retrieve files without actually having a user account on the remote host. The format for ftp is: ftp host or ftp Internet address This will prompt the user for userid and password for the remote system and will then display the ftp prompt (ftp>). At the ftp> prompt, issue the appropriate command (get, put, append, dir, help, etc.). When finished, simply enter quit. Ftp has online help available. For a list of all ftp commands enter 2 Telecommunications & Internet help. For help on a single ftp command enter help command (ex.: help get). Selected ftp commands are listed at the end of this document. Electronic Mail The most widely used Internet service is Electronic Mail (SMTP or simply mail). We all routinely send and receive mail over ACENET, and mail can be sent to colleagues on remote hosts just as easily and in the same way. The only difference is that the mail address must include the receiving party's userid and domain name. For example, to send mail to Gene Smith at Texas A&M simply address it to gsmith@taex001.tamu.edu (let's please not fill up his mailbox for now). If you want to know a colleague's E-Mail address, call him or her and find out. You can also enter several colleague's addresses into a personal mailing list on ACENET for convenience. If you are involved in national or regional projects, you will find that mail over the Internet is very helpful in bringing collaborative efforts to completion quickly. Please be sure that any mail you send over the Internet is ASCII (text format, not a wordprocessing document). Some major Universities still do not have full Internet access or the ability to use Internet mail. These Universities typically use Bitnet to send and receive electronic mail. The Division of University Computing VAX computer in Parker Hall is Auburn's Bitnet mail gateway, and all Bitnet mail must be relayed through the DUC VAX. The address format for Bitnet mail is as follows: userid%Bitnet_Node@ducvax.auburn.edu For example, to send mail to Sullivan@uga use the following address: sullivan%uga@ducvax.auburn.edu Most major Bitnet sites are attempting to get on to the Internet as quickly as possible, and all Land Grant Universities should be connected by the end of 1992. Thus, Bitnet is a short run solution for mail. Frequently Used ftp Commands ! escape to the shell append append to a file ascii set ascii transfer type bell beep when command completed binary set binary transfer type bye terminate ftp session and exit cd change remote working directory close terminate ftp session delete delete remote file dir list contents of remote directory disconnect terminate ftp session 3 Telecommunications & Internet get receive file help print local help information lcd change local working directory mget get multiple files mkdir make directory on the remote machine mput send multiple files prompt force interactive prompting on multiple commands put send one file pwd print working directory on remote machine quit terminate ftp session and exit rename rename file status show current status ? print local help information Frequently Used telnet Commands ^] escape to telnet command mode (Control-Right-Bracket) close close current connection display display operating parameters quit exit telnet status print status information z suspend telnet ? print help information Frequently Used rlogin Commands ~. disconnect from the remote host -- this is not the same as logout, because the local host breaks the connection with no warning to the remote host ~^Z suspend your login session temporarily (Tilde-Control-Z) (return to your remote session by entering fg at the local host prompt) 4 Telecommunications & Internet 3/3/92 5