Do this in the hardware layer of your network. Software is way down the line and the mac addressing schemes should already be applied. Use a router, port forwading, and Firefox.
With the router you can assign the mac addressing scheme for authenticated computers. Port forwarding you can use to allow WAN access to the correct PC on the routed network. Firefox lets you save user names and passwords with a master password so you don't have to type them in each time. For LAN just include which mac addresses can access the resources (ip:port).
And -=always-= use a firewall. Set it up to allow HFS.exe to allow incoming connections over a certain port. Forward that port to through the router. When you connect through the browser, use
http://yourdomain.net:port and it'll get forwarded. That would be for WAN access but would also work for local access.
You end up with a restricted LAN which is the only way to go using wireless, plus you can still access it from anywhere else in the world using the right login credentials via HFS. If you have a dynamic IP, check out
this post and get your own domain. Very simple to implement.
