I have a Mac mini, running El Capitan, which I use as a media server. I access/control it and control it via screen-sharing. The Mac Mini has no display attached, so it must remain connected to my Wi-Fi or I can't access/control it.
There is however no need for it to be permanently connected to the internet. Beyond the security risk, it also uses up bandwidth for background tasks which I have no use for.
I would like to disable web access, while keeping Wifi connectivity. Possible? How?