We wanted to use client certificates in browsers for some of our users for machine identification. I set up a CA and and signed a client certificate which I installed in chrome.
Then I set the following in apache:
On our test server this worked perfectly. chrome asked to use the client cert and the client cert details were available in php.
When I moved the CA and the settings over to our production server, this didn't work. Chrome didn't ask about the certificate and php didn't get any of the client cert details. The only difference that I can think of between the 2 servers is that on the test server we're using a self-signed cert.