Hey,
So I just checked your cert against Qualy’s SSL test:
https://www.ssllabs.com/ssltest/analyze.html?d=ssl.comodo.com
The server does not support Forward Secrecy with the reference browsers. Additionally, you are not using the latest TLS v1.2
Why PFS: Pushing for Perfect Forward Secrecy, an Important Web Privacy Protection | Electronic Frontier Foundation
SSL Labs: Deploying Forward Secrecy | Qualys Security Blog
Any plans for this implementation soon? ;D