Normal behavior of the Ban is to prevent access to the addresses you specify (also called black-list).
If you want the opposite, to allow the addresses that you specify (white-list), enter all addresses in a single row preceded by a \ character.

Let say you want to allow all your 192.168 local network plus your office at 1.1.1.1.
Just put this IP address mask: \192.168.*;1.1.1.1
The opening \ character inverts the logic, so everything else is banned.

If you want to know more about address masks, check the guide.