<VirtualHost 127.0.0.1:443>
SSLEngine on
SSLVerifyClient require
SSLVerifyDepth 2
SSLCACertificateFile /etc/ssl/cacert.crt
SSLCertificateFile /etc/ssl/certs/cacert.crt
SSLCertificateKeyFile /etc/ssl/private/cacert.pem
SSLOptions +StdEnvVars

ServerName secure.cacert.org
DocumentRoot /www
</VirtualHost>

if($_SERVER['HTTP_HOST'] == "secure.cacert.org")
{
$query = "select * from `users` where `email`='$_SERVER[SSL_CLIENT_S_DN_Email]'";
$res = mysql_query($query);
if(mysql_num_rows($res) > 0)
{
$_SESSION['profile']['loggedin'] = 1;
header("location: https://secure.cacert.org/account.php");
exit;
}
}