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Salmander's avatar
Salmander
Icon for Nimbostratus rankNimbostratus
Sep 30, 2020

SSL Handshake errors - no additional information in ltm log - v13.1.3.5

Hi. I need to troubleshoot some SSL Handshake errors and I understood that additional logging should already be available in the LTM log but it is not on my v13.1.3.5 LTM-VE. I have tried changing the log.ssl.level value to Debug but it has no effect. I want to understand what cipher the external client is sending in with as our ciphers for this SSL Profile:Client is set to DEFAULT

 

Please can anyone advise?

BIG-IP
security
ssl
  • Enes_Afsin_Al's avatar
    Enes_Afsin_Al
    Icon for MVP rankMVP
    Sep 30, 2020

    Hi Salmander,

    Can you try this iRule?

    when HTTP_REQUEST {
	log local0. "Cipher=[SSL::cipher name] - Version=[SSL::cipher version] - Bits=[SSL::cipher bits]"
}
    • Salmander's avatar
      Salmander
      Icon for Nimbostratus rankNimbostratus
      Sep 30, 2020

      Thanks for the reply. That works well for traffic which is successfully processed by the F5 but does not appear to work for traffic that is reported by the "SSL Handshake failed for TCP" issue.

       

      I have added Source IP Address=[IP::client_addr]:[TCP::client_port] to your iRule so the source IP address and source port is reported in the log, but the iRule does not appear to be run for the traffic that has the SSL Handshake error by verifying the source IP address/port details

  • Lidev's avatar
    Lidev
    Icon for Nacreous rankNacreous
    Oct 01, 2020

    Hi Salmander,

     

    You can use SSLDump to troubleshoot your SSL Handshake issue.

    • https://support.f5.com/csp/article/K10209
    • https://support.f5.com/csp/article/K15292

     

    Regards