Host Wi-Fi Access Point without tethering How can I make my MacBook host a WPA2-encrypted wireless access point without tethering?

I don't want to share my Internet connection and I don't want an ad-hoc network, instead I want to host a real /24 closed Wi-Fi network using just my MacBook.
I'm not sure how to provide it with a specific network range however the best way to make an ad-hoc network on your Mac is to disconnect from any other network (as you mentioned you don't want to share a connection you want to make a new one), open System Preferences -> Sharing -> Internet Sharing and share wireless over wireless, it should give you the option to configure your SSID and Security from the same settings page.Hope this helps!