Mac authentication lets you specify mac addresses which will not go through the splash page and can be automatically use the internet for free. Only local MAC authentication is supported.
Here is how to set up local macauth (so those mac addresses will skip the splash page and access is automatically):
You need to edit a configuration file on the router to perform this operation.
So, you need to SSH to your router using an ssh client like Putty, the same way you did when you set up the router.
Once you are in the router, type the following:
sudo vi config
If you are using a different interface than eth1 (which you selected in the control center before you copied the install script), then you need to change to that directory instead of eth1.
Scroll down to:
# LOCAL MAC addresses
press the INSERT button on your keyboard and, remove the
# symbols and change the XX’s values to the MAC addresses values
press the ESC (escape) button on your keyboard. Type “:wq”
Reboot your router.