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prashanth's avatar
Icon for Nimbostratus rankNimbostratus
Dec 04, 2020

Cipher negotiated between F5 and Node

Hi There, We are currently in the process of upgrading F5 from v12 to v13. We came across an issue due to depreciated ciphers. Some of our VIPs were using the DEFAULT cipher suite and since some l...
  • jaikumar_f5's avatar
    Dec 06, 2020

    Here's what you could had done,

    1. ​Run the tmm --clientciphers <suite> command in both the versions and see the difference. Don't forget to frame the command with your existing cipher suite.

    ​2. As you suspect the issue is on the server side, you can run the same command like,

    tmm ---serverciphers <suite> and identify the differences. If it's DEFAULT, use DEFAULT.

    3. Other option is to use the openssl/curl command to be run against your nodes to see which cipher was selected. I prefer openssl.

    4. The easiest way would be to map an irule to log the ciphers. If you want client side, use clientssl_handshake event, since you need on serverside, use serverssl_handshake event and log below entries.

    SSL Version - [SSL::cipher version]

    Cipher Name - [SSL::cipher name]

    Bits Strength - [SSL::cipher bits]

    If you need help in framing Irule, let us know.​