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chjunti's avatar
chjunti
Icon for Nimbostratus rankNimbostratus
Feb 10, 2025

Help with Configuring F5 Big-IP for SSL Offloading

I’m currently configuring SSL offloading with my F5 Big-IP device, and I’m running into a few issues. Specifically, I’m having trouble with the SSL certificates not being recognized after the offload is set up. Has anyone else experienced this or have suggestions on what I might be missing?

Thanks so much!

application delivery
cloud
  • boneyard's avatar
    boneyard
    Icon for MVP rankMVP
    Feb 11, 2025

    A bit more detail would help. How are you configuring this, roughly the settings, what kind of certificates and what does not being recognised mean?

  • F5_Design_Engineer's avatar
    F5_Design_Engineer
    Icon for MVP rankMVP
    Feb 12, 2025

    Hi Chjunti,

     

    • Check certificate chain:
    • Use a certificate chain validator tool to verify if all intermediate certificates are present. 
    • Import the full certificate chain:
    • If necessary, re-import the certificate chain into the F5, ensuring all intermediate certificates are included. 

      To check the certificate chain and ensure all intermediate certificates are present on your F5 LTM, you can use the following steps:

      Checking the Certificate Chain

      1. Verify the Certificate Chain:
        • Use the openssl command to verify the certificate chain and ensure all intermediate certificates are present.
        • Command:
          openssl verify -CAfile /path/to/chain.crt /path/to/certificate.crt
        • Explanation:
          • openssl verify: Command to verify the certificate.
          • -CAfile /path/to/chain.crt: Specifies the file containing the chain of certificates.
          • /path/to/certificate.crt: The certificate to be verified.

      Importing the Full Certificate Chain

      1. Transfer the Certificate Files:
        • Use SCP (Secure Copy Protocol) to transfer the certificate and chain files to the F5 system.
        • Command:scp /local/path/to/certificate.crt admin@<F5_IP>:/config/ssl/ssl.crt/ scp /local/path/to/chain.crt admin@<F5_IP>:/config/ssl/ssl.crt/
      2. Import the Certificate and Chain:
        • Use the tmsh command to import the certificate and chain into the F5 system.
        • Commands:tmsh install /sys crypto cert <certificate_name> from-local-file /config/ssl/ssl.crt/certificate.crt install /sys crypto cert <chain_name> from-local-file /config/ssl/ssl.crt/chain.crt
      3. Create or Modify the SSL Profile:
        • Ensure the SSL profile is configured to use the full certificate chain.
        • Steps:
          1. Log in to the F5 Configuration utility.
          2. Navigate to: Local Traffic -> Profiles -> SSL -> Client.
          3. Create a new profile or modify an existing one.
          4. Assign the certificate and chain to the profile.

      Example Commands

      Verify Certificate Chain

      openssl verify -CAfile /config/ssl/ssl.crt/chain.crt /config/ssl/ssl.crt/certificate.crt

      Import Certificate and Chain

      tmsh install /sys crypto cert mycert from-local-file /config/ssl/ssl.crt/certificate.crt install /sys crypto cert mychain from-local-file /config/ssl/ssl.crt/chain.crt

      Assign Certificate and Chain to SSL Profile

      1. Log in to the F5 Configuration utility.
      2. Navigate to: Local Traffic -> Profiles -> SSL -> Client.
      3. Create a new profile or modify an existing one.
      4. Assign the certificate and chain to the profile.

      By following these steps, you can ensure that the full certificate chain is correctly imported and configured on your F5 LTM. 

      Test and share the status update and let me know for further help.

    Kindly rate

    HTH

    F5 Design Engineer