Hi silviudusa,
Thanks for trying NeoRouter.
It depends. What do you want to protect and against what?
If just want to protect your linux box from Internet attacks, I think your current design is OK, since you put your Ubuntu box behind the firewall and all rules should be set in the ClarkConnect. Though NeoRouter server opens a port to the Internet, it's designed to handle most network attacks (
http://tldp.org/LDP/nag2/x-082-2-firewall.attacks.html). So you don't need to worry about it.
If you want to protect from other computers in the same LAN behind your firewall, you may want to setup the firewall on your linux box.
BTW, NeoRouter has a built-in firewall feature, which can be used for protecting a computer from others in the virtual LAN.
Thanks,
KevinZ - NeoRouter team