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This page aims to provide you with a step-by-step guide on how to use public key authentication for external login to the NHR systems at the Berlin (NHR@ZIB system "Lise") and Göttingen ("Emmy") sites. It also provides information for internal login to connect between NHR nodes in Berlin/Göttingen.

Summary

1. Create an SSH key pair with a passphrase that is not used anywhere else.
2. Upload your public key on our Portal NHR@ZIB.
3. Specify your private key when connecting to our login nodes (either via ssh -i <your_private_key_file> or in your local SSH configuration).

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An SSH key pair consists of a public key and a private key. The public key is used to encrypt messages. Such messages can only be decrypted using the corresponding private key. For this reason the private key must be stored safely on the local machine - protected by a passphrase, and not accessible for by other users.

SSH Key Generation

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The current ssh host keys for

• glogin[1-9].hlrn.de
• blogin[1-6].hlrn.de

are:

SHA256:mrwKbHEz3pJCmvU7ZEXoIKxVRz0E9/4GDp3k41x4Q8g (RSA)
SHA256:53WD36v+IjHObgS3DbjIi+zShcQ/MCAIqJNgJOlfR08 (ED25519)
SHA256:pNGlm//LyjJZi6tX0mz5SPSs4IBkuyJI/iWI10JbhgE (ECDSA)

For

• bgnloginbgnlogin[1-2].nhr.zib.de
• bgilogin[1-2].nhr.zib.de

the fingerprints are:

SHA256:rusM3G/8eG7ZFLNJtvymL/wNHFGgkOFTMYCBk3yLiL8 (ECDSA)
SHA256:8/hSIv0HfMDEy1gUQjVmb0cUMDztgacNfXSBUzcgCFM (ED25519)
SHA256:WulefLWFPRPPobUI6/+4bJpttV9SlQhZ0prEo8ELp1k (RSA)

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Before you can log in to one of the Berlin/Göttingen NHR@ZIB login nodes, make sure you have uploaded your SSH public key (not the private one) at the Portal NHR@ZIB. Here you can also view or remove public keys uploaded earlier (if any).

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You can upload up to seven SSH public keys at the service portal.

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For external connections to the NHR NHR@ZIB login nodes in Berlin/Göttingen the private key of the SSH key pair is needed. Recall the name and the location (see above) of the file containing the private key. 

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With the -i option to the ssh command you can specify the full path of your private SSH key file when you log in to one of the Berlin/Göttingen NHR@ZIB login nodes. You will be asked for the passphrase of your private key.

Example for a login to blogin (Berlin):

$ ssh -i $HOME/.ssh/id_rsa_nhr -l your_username blogin.hlrn.de
Enter passphrase for key '/<home_directory>/.ssh/id_rsa_nhr':
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SSH for internal connections between a Berlin and a Göttingen login node nodes of Lise works right out of the box - that is, without specifying any keys. This also applies to SSH connections between nodes of the same site. This is enabled through host-based authentication which is active by default.

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