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This page provides information about how to use telnet to access remote computers.

Before you Proceed

This what you need to know to use Telnet (or ssh):

• Your current UNIX user name and password

If you do not have the information listed above then go to this page.

What is Telnet?

Telnet is a protocol used to remotely log onto a computer system to perform tasks on that remote computer using a command line interface. Even desktop computers, especially ones using an operating system based on UNIX (like Macintosh computers running Mac OS X) can support remote users using telnet or its more secure alternative, ssh.

Telnet and security

Telnet was initially developed in 1969. Most users of networked computers were then in the computer departments of academic institutions, or at large private and government research facilities. In this environment, security was not nearly as much of a concern as it became after the bandwidth explosion of the 1990s. The rise in the number of people with access to the Internet, and by extension, the number of people attempting to crack other people's servers made encrypted alternatives much more of a necessity.

Experts in computer security, such as SANS Institute, recommend the use of telnet for remote logins should be discontinued under all normal circumstances, for the following reasons:

• Telnet, by default, does not encrypt any data sent over the connection (including passwords). It is often practical to eavesdrop on the communications and use the password later for malicious purposes; anybody who has access to a router, switch, hub or gateway located on the network between the two hosts where telnet is being used can intercept the packets passing by. They can obtain login and password information (and whatever else is typed) with any of several common utilities like tcpdump and Wireshark. Then they can use that login and password to access confidential information and/or your Email.
• Most implementations of telnet has no authentication to ensure that communication is carried out between the two desired hosts and not intercepted in the middle.
• Commonly used telnet tools have several vulnerabilities discovered over the years.

These security-related shortcomings have seen the usage of the telnet protocol drop rapidly, especially on the Internet, in favor of the secure shell (SSH) protocol, first released in 1995. SSH provides much of the functionality of telnet, with the addition of strong encryption to prevent sensitive data such as passwords from being intercepted, and public key authentication, to ensure that the remote computer is actually who it claims to be. You can usually use SSH instead of telnet by simply substituting "ssh" for the word "telnet".

Telnet Instructions

Note: If you wish to use the command line Email tool PINE you must make an Internet connection with your ISP or a "PPP" connection to SJSU before you can use telnet. (See instructions for "PPP” connections.) For these instructions we will assume you wish to log onto the main SJSU UNIX server zeus.sjsu.edu.

Using a Windows PC

After you have made a connection to the Internet. On Vista computers you have to enable Telnet before you can use this protocol:

1. Click on Start
2. Choose Run
3. In the box that appears, type: telnet zeus.sjsu.edu
4. Click OK
   Note: telnet is a command your operating system will recognize as the signal to connect to the server or remote server you have named, in this case, zeus.sjsu.edu
5. You should have a screen in front of you that asks you to log in;
6. type your USERID and press enter.
7. Type in your Unix E-Mail password and press enter.
8. The system will tell you things about our E-Mail policy, and then you will see:
   The default terminal type is VT100 term = <VT100> “ - press enter to accept the default type. Now you should see this: (See note below)
   home>your userid> your cursor will be here. You are set to go.

Using Mac

After you have made a connection to the Internet:

1. Double click on Hard Drive folder
2. Double click on Application folder
3. Double click on Utility folder
4. Double click on the Terminal window
5. In the box that appears, type: telnet zeus.sjsu.edu
6. Click OK
   Note: telnet is a command your operating system will recognize as the signal to dial out to the server you have named, in this case, zeus.sjsu.edu
7. You should have a screen that ask you to log in; type your USERID and press enter.
8. Type in your Unix E-Mail password and press enter.
9. The system will tell you things about our E-Mail policy, and then you will see:
   The default terminal type is VT100 term = <VT100> - press enter to accept the default type. Now you should see this:
   home>your userid> your cursor will be here. You are set to go.

Enabling Telnet on a Vista Computer

As stated before there are security concerns regarding the use of telnet. That is why it is turned off by default!

You can install telnet by following these steps:

1. Open the Programs and Features Control Panel applet (Start, Control Panel, Programs and Features).
2. Select "Turn Windows features on or off."
3. Select the Telnet Client option and click OK.
4. A dialog box appears, confirming the installation of new features. After installation is complete, close the main Programs and Features Control Panel applet. The telnet command should now be available.

Resources

Telnet support documentation is available for download in PDF format.

Need more information?

If you did not find what you are looking for on this site the SJSU Help Desk can help you:

• Call us at (408) 924-2377 during our normal business hours.
• Or, go to our ticket portal and submit an incident ticket into our ticketing system.
• Or, visit us in Clark Hall room 102 during our normal business hours.

Missing Links, Errors and Broken Links?

We try to keep this and every page in our Website up to date. If you know of a resource we are not listing, find an error and/or a broken link we apologize. Please let us know about the error so we can fix it. It would be most helpful if you could copy the URL of the page with the missing resource, error or broken link, and provide information about where the error or the broken link is in the page. Please do one of the following:

• Call us at (408) 924-2377 during our normal business hours.
• Or, go to our ticket portal and submit an incident ticket into our ticketing system.
• Or, visit us in Clark Hall room 102 during our normal business hours.