title: How do digital certificates work when used for securing websites (using SSL)?
body: <p>Please help me understand how the process goes. I understand that web browsers contain root certificates for certificate authorities (CAs) like verisign, Entrust, Comodo .. etc, but what exactly happens when a user accesses a secure page? Does the web browser send a request to the server of the CA to verify the ceriticate or it just uses the CA's root certificate (in the browser) to verify the certificate?</p>
  
  <p>I used some HTTP sniffer and logged on to  gmail (the login page is secure) but didn't see requests going to any websites other than google, does that mean it only uses the CA's root certificate?</p>