Getting started

Basic Linux requirements

Please note that all of our HPC systems are running under Linux, so a basic knowledge of the Linux command line is essential. There are numerous excellent tutorials around the web for a first introduction to Linux and its shell and we think one of them can be found here.

Remote access

For security reasons, our cluster systems are only available from inside the University's domain IPs. If you want to access the systems from outside, you need to set up a VPN connection. See the ZID instructions for setting up a VPN client for various operating systems.

Login procedure

Depending on your account use the appropriate login node (also referred to as head-node or master-node) of one of the following systems:

Cluster Login node RSA key fingerprint
LCC 09:a4:3e:1b:46:6b:b3:9a:25:fa:d6:28:a1:68:ca:9a
LCC2 41:29:44:5c:d7:6f:5e:7f:e6:a9:88:54:31:55:74:c3 (RSA)
44:ec:e0:1e:60:b0:9f:64:77:c4:64:ab:a9:42:77:85 (ECDSA)
LEO3 f8:dc:6a:66:de:01:b3:4e:3a:a8:9e:91:be:04:37:56
LEO3E 74:c9:c1:8f:b6:33:b6:68:04:58:60:f4:e7:85:65:0a (RSA)
16:4e:af:09:cc:11:7a:21:4b:7c:e4:97:1f:d6:33:0a (ECDSA)
MACH 37:73:78:35:fe:9a:25:fb:fe:b6:c7:e6:a0:12:bc:e3

Linux workstation

Access to each of the systems listed above is provided via SSH. In Linux, login to the head node of your choice by executing the following command in your local shell:

ssh -l username login-node

At first login, the login node's SSH public RSA key is not registered on your computer yet. If you get the following warning, compare the given fingerprint with the table above before continuing:

The authenticity of host 'login.node (IP)' can't be established.
RSA key fingerprint is ... .
Are you sure you want to continue connecting (yes/no)?

To enable X11 forwarding, necessary for programs with graphical user interfaces such as graphical editors or the graphical interfaces of Matlab, the TotalView debugger, etc. simply add the -X option to the command line above:

ssh -X -l username login-node

Windows workstation

To access a Linux server from a Windows workstation, you need a terminal emulator that supports the SSH protocol and an X-Windows server. We recommend the following:

PuTTY as SSH client and terminal emulator

Install the PuTTY client to establish a remote connection to our HPC systems and to provide you with a terminal (command line interface) to the login node on your Windows system. When opening PuTTY, simply enter the fully qualified domain name of the desired login node into the "Host Name"-field and klick the "Open" button. You are then asked to enter username and password and are subsequently provided with the Linux command line. If you do not get PuTTY's login session dialog box automatically, select the 'Session' panel from its left-hand selection menu.

If you are connecting for the first time, you are presented with an RSA fingerprint and asked for its authenticity. To play it safe, compare the given fingerprint with the table above before continuing.

Further usage instructions can be found at this ZID page. PuTTY is also available via the University's free software download area.

Installing a local X server

In order to open X Windows applications, such as graphical editors or the graphical interfaces of Matlab, the TotalView debugger, etc. remotely on your local Windows PC, you need to have a local X server installed. The two products we recommend in this context are either Exceed from the Open Text Connectivity Solutions Group or Xming. Both X servers can be obtained from the University's software download area by all University employees. An outdated Public Domain release of Xming can be found at Since this version is defective (e.g. dysfunctional clipboard integration), we definitely recommend to use the new Xming version available in the ZID software download area.

Enabling X11 forwarding with PuTTY

X Windows applications called from whichever terminal emulator you use, will only work on your Windows PC if X11 forwarding via ssh was enabled, and of course, only if the X server of your choice is up and running. In case of Exceed, a corresponding active program button in the Windows taskbar will indicate a running X server.

Proceed with the following simple steps to configure X11 forwarding in PuTTY:

  • Select the 'Connection->SSH->X11' panel from the left -hand selection menu.
  • Enter into the 'X display location' dialog box. (Usually the Windows X display server will install itself as display number 0 on your local machine; if necessary consult your specific X server's manual.)
  • Check the 'enable X11 forwarding' check box.

Now open your desired SSH session and enter e.g. xclock on the command line to test your X11 enabled connection.

OS X Workstation

Install the XQuartz SSH Client and X Server, then follow the instructions for Linux workstations.

Change your password

Change your password by issuing


on the command line. After having typed your current password you have to input your new password twice.

Note: Your password should at least be 8 characters long, contain upper and lower case letters, as well as numbers or symbols, to be considered reasonably secure.

File transfer

To transfer your files from and to our systems, we recommend the following methods:

Linux workstation

Use the command line scp program to transfer your files. To upload a file to a destination on a HPC system, use a command similar to the following:

scp SourceFile username@login-node:directory/TargetFile

You can omit the specification of TargetFile if you want to leave the file's name unchanged. Conversely, to transfer a file from a HPC system to your local current directory, issue

scp username@login-node:directory/TargetFile SourceFile


  • Use scp -r ... to copy entire directories recursively, but be very careful, as scp resolves symbolic links to their destination and blindly copies every file it finds this way across the network!
  • To avoid the above problem with symbolic links, or if speed is an issue, use rsync instead of scp, especially when you need to update small differences in large datasets, which exist on both ends.

Windows workstation

Use the open source free SFTP client WinSCP for file transfer from and to a Windows system and see the ZID's howto for a quick introduction to WinSCP usage.

WinSCP is also available via the University's free software download area.