ip range

> I have just installed my firewall a few days ago, and I
> have a small home network that is connected via a
> broadband router. I'm using DHCP and everynow and then, I
> get assigned a new ip address, as shown below.
>
> 192.168.1.100
> 192.168.1.101
> 192.168.1.102
>
> I'm tring to configure my firewall by entering a ip
> range. I've tried entering 192.168.1.100 - 192.168.1.102,
> but with that range, it doesn't work. It does work,
> however, if I enter 192.168.1.*. Doesn't sound better
> entering a ip range instead for security?
>
> Any suggestions and how I would accomplish this?
>