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NUCUSER's avatar
NUCUSER
Icon for Cirrus rankCirrus
Apr 14, 2021

SSL Client Certification Alert 46 Unknown CA

We are seeing 'Alert 46 Unknown CA' as part of the initial TLS handshake between client & server. From a wireshark capture, the 1st Client Hello is visible, followed by the 'server hello, certificate...
application delivery
BIG-IP
LTM
security
  • spalande's avatar
    spalande
    Apr 15, 2021

    Cool. If it's a web based application and browser is the client then yes it would be present. But if it's API call with server to server communication they might need to install it explicitly.

    ​

    ​Also, other thing I would check on the F5 clientssl profile, if CA cert is correctly added to the chain (in case it's not bundled with the server cert)? Meanwhile, please verify that part as well.

  • NUCUSER's avatar
    NUCUSER
    Apr 21, 2021

    Update - Thanks for all your suggestions, most helpful!! This turned out to be a client side cert password issue, client cert re-installed and now working.

Lidev's avatar
Lidev
Icon for MVP rankMVP
Apr 14, 2021

Hi,

You can try to decode TLS records with SSL dump to better understand the root cause and see which part fail.

Please refer below link to get information :

K10209: Overview of packet tracing with the ssldump utility

 

Also, uncheck the Generic Alert options on your Client SSL profile and increase the log level SSL on your F5 to obtain perhaps more details in the ltm log.

 

Regards