How to log on to other computers

On regular computers running Windows usually only one person can be logged on, and that person has to have physical access to the computer. You can avoid the need for physical access to the computer by using a Terminal Services Client (available for all versions of Windows), but you need a server-version of Windows to allow more than one user to be logged on at once. This doesm not apply to computers running *nix[1]. On these systems you can log in and execute commands without physical access to the computer. Thus, you should never shut down a *nix-system before you have checked if there is someone else logged onto it. You can check it by running the command w.

Prerequisites

Prerequisites to be able to log on to another computer are:

1. The computers have to able to communication through a network connection.
2. The computer you want to log on to have to support remote login.
3. The computer you want to log on must be configured to allow you to log on.
4. The computer you are physically accessing got to have software which makes it able to communicate with the other computer.
5. You got to have user access to the computer, that is, you cannot log on to a computer through a network if you cannot log on to the computer when you have physical access to it.

Almost all UNIX-systems at campus fulfill these requirements. Most Windows-systems have software that fulfills the requirement in item 4.

To log on to another computer you need to know the IP-address for the computer. An IP-address is a unique address which consists of four numbers between 0 and 255 divided by dots, e.g. 129.241.56.182. Fortunately most computers have a more logical and readable name associated with the IP-address. This name can be e.g. login.stud.ntnu.no.

Log on to a Windows-system

If you want to log on to a computer running Terminal Services you can install Terminal Services Client. All server-versions of Windows NT, 2000 and XP are running "Terminal Services". It's also installed, but deactivated in Windows XP Professional (you can activate it through Start -> Control Panel -> System -> Remote -> Allow users to connect remotely to this computer).

Connecting to NTNU's terminal servers from a Windows client, start the Remote Desktop Client from Start -> Accessories -> Communications -> Remote Desktop Connection. Type in tsstud.stud.ntnu.no and click Connect.

To connect to a Windows-system which does not have a server-installation you first have to install software to enable it, e.g. VNC. VNC enables you to remotely control a computer, but more than one user cannot use the computer at once. In practice this means that there is only one mouse pointer, and if someone is physically logged to the computer you have to "fight" about controlling the mouse pointer.

To connect to a Windows-system from a UNIX-system can install e.g. Remote Desktop.

Text-based login in *nix

If you want to log on to a computer to do tasks which do not need a graphical user interface like reading e-mail with Pine, or edit text with vi/vim you have to use a SSH-client. None of the computers at campus supports Telnet or rsh, so you have to use SSH, which is a secure protocol with password encryption. When you're using SSH at NTNU you usually have to use login.stud.ntnu.no (students) or login.ansatt.ntnu.no (employees) unless you're connection to server which belongs to a specific faculty.

Graphical login i *nix

When you want to use programs with a graphical user interface from a remote computer, which uses the X Window System. This requires more of the computer you are using than just text-based login. It has to have graphical system (X Window System, Windows or similar) and run a X-server. If you are using a computer running Linux or UNIX you probably have a X-server running. If you are using a Macintosh, Windows or OS/2-based computer you have to install a X-server which runs in the background. A X-server for Windows is WebTermX which you can download from Progdist or borrow from Orakeltjenesten on the first floor in Sentralbygg II on Gløshaugen.

When you are using a computer which runs a X-server you can log on to a UNIX and run graphical programs.