Test online de servidores web https: https://www.ssllabs.com/ssltest/

Configuración de Nginx para permitir SSL Forward Secrecy y Session Caching.

server {

...

  ########## Forward Secrecy ###############

  ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
  ssl_prefer_server_ciphers on;
  ssl_ciphers "EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !aNULL !eNULL !LOW !3DES !MD5 !EXP !PSK !SRP !DSS";

  ###### Session resumption (caching) ######
 
  ssl_session_cache shared:ssl_session_cache:10m;

...