Network Tools (telnet & ftp)

Computer Methods in Chemical Engineering

Telnet

Telnet is a program that allows one to login from one computer to another computer. When various disparate computers are networked together, there must be a means of having them communicate among one another in a mutually understandable manner. The remote computer can be located next room or half way around the world. In general, one logs onto a remote computer with telnet with full privileges of running all sorts of application programs as if one is directly logged into that remote computer. A more secure version of telnet is "ssh" (download a PC Windows version from UMCP).

ftp

File Transfer Protocol (ftp), on the other hand, is a program that allows one to transfer files from one computer to another. Thus, http (Hypertext Transfer Protocol) used in internet browsers in a sense can be considered as a special case of ftp. Unlike telnet where you can do much more, ftp performs only file transfer or actions closely related to transferring files (e.g., cd, delete, etc.). A handout that describes ftp (and ssh ftp) can be found at: http://www.helpdesk.umd.edu/documentation/other/ftp.shtml. A more secure version of ftp is "scp" (download a PC version from ssh or WinScp from here).

Why are these two programs (telnet & ftp) important?

If you have accounts in more than one computer (e.g., two UNIX computers or a PC and a UNIX), then you know you want to have access to more than one computer from the same terminal. Thus, you need telnet for remote login. As much as you use "copy" (DOS), "cp" (UNIX), or drag-and-drop operation (Windows) to copy files from one disk or from one directory to another, you use ftp to move files between computers. On some computers, these program may be called something other than telnet and ftp, but they serve fundamentally the same function.

Other Internet Programs

Program Function Unix Example
archie Find the location of a specified file archie monopoly
finger name@host Find information on the given user & display his .plan file. finger nsw@umd.edu
whois Find a person whois -h glue.umd.edu wang
gopher host Find topic among different sites in a gopher server gopher veronica.scs.unr.edu
veronica Find topic among different gopher  
talk On-line communication with another user who is currently logged in. talk nsw
irc Chat interactively with a group of people in an internet chat group  
news Read articles in news groups  
email Read/send e-mail mail nsw@umd.edu

Anonymous Login

The advent of internet allows you to access information on someone else's computer without having an account on that computer. There is a lot of public domain software or shareware that you can download from the internet. Likewise, there are also a lot of documents and books you can download. You accomplish this through anonymous login. When telnet or ftp is a stand alone program, you issue anonymous as the username, and a password is usually either not required altogether or your e-mail address suffices. (Be sure you spell anonymous correctly.) When telnet or ftp is imbedded as part of a network browser (e.g., Netscape or Internet Explorer), you issue it with an input line with the following format:
"ftp://computer/directory/filename".

Major depositories of old public domain software:

Search for Information/Software on the Internet

Examples of Some General Search Engines: Examples of Some More Specialized Search Engines:

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Computer Methods in Chemical Engineering -- Network Tools
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Nam Sun Wang
Department of Chemical & Biomolecular Engineering
University of Maryland
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e-mail: nsw@umd.edu ©1996-2006 by Nam Sun Wang
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