Login servers
From StackWiki
When your Stack account is created, you can login to several servers at Stack, each maintained by the Unix Committee. These servers are generally referred to as the login servers or shell servers.
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Summary of login servers
Below is a list of the systems that are available to users by default, along with a short description.
Primary systems, with high levels of support:
- toad.stack.nl: 4-core Opteron server with 4GB RAM, running FreeBSD 7 in 64-bit mode;
This system is not available for graphical ("X") logins and X software is not installed. - snail.stack.nl: 2-cpu Athlon server with 2GB RAM, running FreeBSD 7 in 32-bit mode;
This system is available for graphical logins and a lot of graphical software is installed. - turtle.stack.nl: 2-cpu Athlon server with 2GB RAM, running FreeBSD 7 in 32-bit mode;
This system is available for graphical logins and a lot of graphical software is installed. - hammer.stack.nl: 2-core Opteron server with 4GB RAM, running FreeBSD 7 in 64-bit mode;
This system is available for graphical logins and a lot of graphical software is installed.
Secondary systems (reduced application support):
In development:
- lobster.stack.nl: zone on helsinki (2-cpu UltraSPARC server with 8GB RAM), running Solaris 10 in 32/64-bit mode;
This system will replace crab (which is no longer available). It is currently in development, but accounts are created on demand (contact Unix Committee).
Connecting via SSH
Members have shell-access on our machines. This means you can log in to them and run commands locally. The most commonly used way to do this is using ssh. The communication is encrypted and fairly secure.
From a Linux or *BSD machine it is possible to log in with the command ssh. From Windows it is possible to use the program putty. It is also possible to use the program SSH Secure Shell.
As of 2009, support for the unencrypted 'telnet' protocol has been dropped for security reasons. Please use SSH to login to the Stack servers.
todo: say something about ^? vs ^H
todo: add a link to unix commands
File Transfer
SSH servers support secure file transfer. A command line program is available in UNIX systems.
sftp <username>@<servername>.stack.nl
connects to the server for secure file transfer. Graphical interfaces like KDE and Gnome also have their user friendly clients. Under KDE, just launch Konqueror or "Home Folder" and write
sftp://<servername>.stack.nl
in the address line. Under GNOME, click "Connect to server" under Locations, choose SSH as protocol and fill in the form.
SSH Secure Shell has a file transfer client for MS Windows. It is preinstalled in TU/e computers. You can also get the freeware version from official site.
X-Windows login
Unix users
If you are working under some *nix (Linux, BSD, Solaris etc.) environment, you most probably have an X server running. The terminal command
ssh -X username@server.stack.nl
enables X forwarding so you can run X programs on Stack servers with GUI. The graphical extensions provided by this connection are basic; you can try
ssh -Y username@server.stack.nl
to increase the graphical capabilities of the connection. In case of problems, you can fall back to -X. If you use Solaris, only -X is supported but this will incorporate the graphical extensions. Running graphical applications with ssh -X is also possible from MacOS X when you have the X server running.
Windows users
If you are using MS Windows, you need an X server to execute graphical aplications. Exceed is officially supported at TU/e. Check out instructions from BCF.
Once you have Exceed installed, you can start an X session by
- Start Exceed an let it run in the background
- Start a regular SSH connection with X-forwarding.
Exceed tutorial
First, launch Exceed from start menu. If you see the little Exceed window somewhere on your screen, you are on the correct path.
Now launch SSH client and enter settings, see the picture:
In the settings, you have to enable X11 forwarding. For that, go to "Tunneling" tab and enable X11 tunneling.
Then you can set the server and username, this is optional but saves time later. Go to "Connection" under "Profile settings" and fill in server and username. See the image on the left. For a full list of servers you can use, see the top of this page.
Now close the settings. SSH will ask if you want to save your settings. If you are on your own computer, you can safely click YES. Now connect to the server by clicking "connect" or pressing Enter or SpaceBar.
Once you are connected, you can launch any graphical application by just typing its name(or sometimes, an alias). You can see Firefox running on hammer. This screenshot is taken on a pc in "PC Zaal" in HG 5th floor, running Microsoft Windows XP on an Intel processor.
