You can test the SSL negotiation of your website using online tools or specific commands. Here are some options:

  1. SSL Labs:
    • Use the free service from SSL Labs to perform a comprehensive analysis of your SSL certificate, including the SSL/TLS negotiation.
    • Simply enter your website URL, and it will generate a detailed report about supported SSL/TLS versions, cipher configurations, and more.
  2. OpenSSL:
    • From the command line, you can use openssl to test SSL/TLS negotiations.
    • Example:
      openssl s_client -connect yourwebsite.com:443

      This will give you details about the SSL handshake process, including TLS version and certificates.

  3. Nmap:
    • Nmap, with the ssl-enum-ciphers script, can help you verify SSL negotiations.
    • Example:
      nmap --script ssl-enum-ciphers -p 443 yourwebsite.com