Is it possible to forward all traffic to an internal IP?

[#1]

I have an internal machine which is running my firewall. Is it possible to forward all traffic to this machine? The setup looks like this

Internal Network (192.168.1.0/24)  <------>(192.168.1.2)  [Linux Firewall] (172.16.1.1) <---- >172.16.1.254 [Technicolor TG582n] --- (Public IP)
The technicolor has a private range of 172.16.1.1/24
I've disabled the firewall on the techicolor, but I want all traffic destined to my public IP to hit my Linux Firewall. Can this be done?

[#2]

The best way to achieve this would be to put the TG582n into bridged mode, and letting the firewall do the rest. This thread has information on the subject.

[#3]

As kmiburn says, bridged mode is proably the best way. You would need to change the WAN setting on the Linux firewall from DHCP ( I assume at the moment ? ) to PPPoE and configure it with your Plusnet username/password. Once done, then your Firewall WAN IP would be your public IP.