Install CA certificates on Linux systems (2024)

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If WiFi is already set up, you only need the final 2 of the 5 following certificates, otherwise you need all of them. Save the certificates in a temporary directory (i.e. C:\Temp), use the names as specified here:

telekom.crt
https://pki.pca.dfn.de/fh-schmalkalden-ca/pub/cacert/rootcert.crt

dfn.crt
https://pki.pca.dfn.de/fh-schmalkalden-ca/pub/cacert/intermediatecacert.crt

hsm-ca.crt
https://pki.pca.dfn.de/fh-schmalkalden-ca/pub/cacert/cacert.crt

iukca3.crt
Download aus CMS

zefica.crt
Download aus CMS

Use the right mouse key to clock on a link, from the context menu chose “Save as”.

Convert certificates to PEM file format

Run

openssl x509 -inform der -in telekom.crt -out telekom.pemopenssl x509 -inform der -in dfn.crt -out dfn.pemopenssl x509 -inform der -in hsm-ca.crt -out hsm-ca.pemcp iukca3.crt iukca3.pemcp zefica.crt zefica.pem

to convert or copy the files to PEM file format.

RHEL 6 and Clones

• Install ca-certificates package

   yum -y install ca-certificates 

• Activate package

   update-ca-trust force-enable 

• Copy PEM files to /etc/pki/ca-trust/source/anchors
  Create the /etc/pki/ca-trust/source/anchors directory if not yet present.
  Copy the PEM files created in the previous step into the directory.
• Integrate certificates into the system's certificate set

   update-ca-trust 

RHEL 7 and Clones

• PEM-Dateien nach /etc/pki/ca-trust/source/anchors kopieren
  Create the /etc/pki/ca-trust/source/anchors directory if not yet present.
  Copy the PEM files created in the previous step into the directory.
• Integrate certificates into the system's certificate set

   update-ca-trust 

Debian and derivatives (i.e. Ubuntu)

• Copy PEM files to /usr/local/share/ca-certificates
  Create the /usr/local/share/ca-certificates directory if not yet present.
  Copy the PEM files created in the previous step into the directory, change the file name suffix to “*.crt”.
• Integrate certificates into the system's certificate set

   update-ca-certificates