Apache2 and the proxy_pass to ssl based websites

Everybody knows this:

ProxyPass / http://domain.tld/ ProxyPassReverse / http://domain.tld/ ProxyPreserveHost on

But what will you do if you have a https based backend?

Some of you will try this:

ProxyPass / https://domain.tld/ ProxyPassReverse / https://domain.tld/ ProxyPreserveHost on

After an apache2 restart you will find this in your logfiles when you request the url.

[Mon Jul 29 13:14:22 2013] [warn] proxy: No protocol handler was valid for the URL /. If you are using a DSO version of mod_proxy, make sure the proxy submodules are included in the configuration using LoadModule.

The point is, you have to enable the ssl module for your apache2.

After that you can:

SSLProxyEngine On ProxyPass / https://domain.tld/ ProxyPassReverse / https://domain.tld/ ProxyPreserveHost on

Reload your Apache2 and be happy.