How to debug a SSL connection with OpenSSL?

1. Install a recent version of OpenSSL (Which version of OpenSSL should I use?), see the website www.openssl.org
2. On your disc: retrieve the extract of the certification roots used by our certificates and present in most browsers. Open the archive in /tmp for example.
   https://www.tbs-internet.com/secure/ca/tracessl-server-certs.tgz
3. Debug with the command:

   OPENSSL=/usr/local/src/openssl-097/bin/openssl
   TRACESSL=/tmp/tracessl-server
   
   $OPENSSL s_client -port 443 -host the.website.to.test -no_tls1 -CApath $TRACESSL
   

   and interpret the results! If the code is 0, then everything is ok!