Redirection :80 -> :443

apache-vhost

<VirtualHost *:80>
        ServerName plop

        RewriteEngine On
        RewriteCond %{SERVER_PORT} !^443$
        RewriteRule ^/(.*) https://%{HTTP_HOST}/$1 [NC,R,L]
</VirtualHost>

<VirtualHost *:443>

        ServerName plop
        SSLCertificateFile    /etc/apache2/ssl/plop.pem
        SSLCertificateKeyFile /etc/apache2/ssl/plop.key

        ErrorLog /var/log/apache2/plop-error.log
        LogLevel warn
        CustomLog /var/log/apache2/plop.log combined
        ServerSignature Off

        DocumentRoot /var/www/plop
</VirtualHost>