1 - Abstract

As there are two different types of certificates, there are two individual tasks as well in order to setup a hosts. client.

• Host Certificate
• Client Certificate

If one would like to use only one certificate, execute the corresponding tasksubtask.

Configuration paths

There are two different options to tell the ssh daemon about the certificate: 'user based' (recommended)  or 'global'


• 'user based': The certificate is valid for one specific user on the client.

  Code Block
  language bash
  SSH_CERTIFICATES=$HOME/.ssh/netdef SSH_CONFIG=$HOME/.ssh/config SSH_KNOWNHOSTS=$HOME/.ssh/known_hosts

  
  

• 'global': The certificate is valid for each user on the client.

  Code Block
  language bash
  SSH_CERTIFICATES=/etc/ssh/netdef SSH_CONFIG=/etc/ssh/ssh_config SSH_KNOWNHOSTS=/etc/ssh/ssh_known_hosts

  
  

2

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To setup the host certificate the public key of the CA authority is needed. There are three public keys called  'yubikey1.pub', 'yubikey2.pub' and 'yubikey3.pub'.

Add the following line to '$SSH_KNOWNHOSTS' where 'yubikeyX.pub' must be replaced with the public key stored in 'yubikeyX.pub'.

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Client Certificate

Step 1 - Sign client's public key

One can either use the public key file that is stored on github or one can manually copy the id_rsa.pub file to the CA authority.

The instructions how to singed a clients public key can be found here.

...

helloworld-1234567890-1-cert.pub
helloworld-1234567890-2-cert.pub
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helloworld-1234567890-N-cert.pub

Step 2 -

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Copy all certificates to netdef folder

Copy all certificates that can be found in the provided tar file to the folder '$SSH_CERTIFICATES'.

mkdir -p $SSH_CERTIFICATES
cp *cert.pub $SSH_CERTIFICATES

Step 3 -

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Edit the config file

Add the following lines to '$SSH_CONFIG'. The name of the certificate as well as '$SSH_CERTIFICATES' must be replaced with the correct file name and the correct path to the folder respectively.

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