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Connect with SSH

To access the Scientific Compute Cluster, you need an SSH client.

Please note, that you can only connect to our frontends from inside the GÖNET, our campus network. If you are not inside GÖNET, you can either use a VPN or connect to first and ssh into a front end from there.

Since May 15th, 2020, authenticitation by password has been deactivated for security reasons. To log on to the frontends an SSH key is required.

Creating SSH Keys

Command Line

On Linux, macOS and the latest Windows 10 Versions SSH is already built in. A key can be generated with the command ssh-keygen -t rsa -b 2048 -f <yourkey>. As soon as you enter the command you will be asked to secure the key with a passphrase. Please do not use keys without a passphrase to log in to our systems.

PS C:\Users\win10-virtual> ssh-keygen -t rsa -b 2048 -f .ssh/id-rsa
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in .ssh/id-rsa.
Your public key has been saved in .ssh/
The key fingerprint is:
SHA256:JIFSfI6/QBdnUaVsjKdHIfCqw1yjZyk96KDp07MlvbM win10-virtual@DESKTOP-N8DT68R
The key's randomart image is:
+---[RSA 2048]----+
|    |
|  . o ooo= o     |
|   . +.++ B      |
|    o o+ =       |
|   . o+ S .      |
|   oo*.o .       |
|  o.O+*.         |
| + =o*o.         |
|+...+Eo          |

This creates both the private key file <yourkey> and a corresponding public key file <yourkey>.pub. Never give out your private key, but always upload only the public key!

Graphical User Interface (PuTTY)

If your Windows Version does not include SSH, you can use PuTTY. “PuTTY is a free implementation of SSH and Telnet for Windows and Unix platforms” and can be downloaded here. If you use PuTTY to connect, you will need PuTTYgen to generate a key, which should be included in you PuTTY installation.

  1. Open PuTTYgen
  2. Click 'Generate' and follow instructions
  3. Enter a passphrase for the key
  4. Save private key

Upload Key

To upload a key, please log into your account on the GWDG Website, go to “My Account”. Then scroll down to “Other Settings” and click “edit”. You can now add a public key.
If you have used the command line tool to generate the key, you can find it under <yourkey>.pub. If you are using PuTTY, you must use the contents of the top box in PuTTYgen, which is the correctly formatted public key.

Connecting to the System

Command Line

Just open a terminal and connect with ssh -i <yourkey> <userid> or ssh -l <userid> -i <yourkey>
If you want to access one of our other frontends you can replace gwdu101 with gwdu102 or gwdu103, For Example:

$ ssh -l mboden -i .ssh/id_rsa
Last login: Mon Apr 20 13:54:52 2020 from
gwdu102:22 14:51:56 ~ > 

Using PuTTY

  1. Open PuTTY
  2. Put in Hostname
  3. Go to “SSH
  4. Select “Auth”
  5. Browse to your key
  6. Click Open
  7. If you secured your key with a passphrase (which we highly recomment), you will be asked to enter it

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