We are trying to understand what a more secure installation is: a) A modem connected to the internet with PPPoE doing a NAT to the firewall than doing a second NAT for all the devices
b) A modem acting like a bridge and the firewall doing the PPPoE?
I guess that more layers could be beneficial for security because malicious connection will get filtered by the modem and the firewall and they would be 2 NAT to go through. But on the other hand the modems are usually vulnerable and not up-to-date devices...
Simply on a security point of view what is the most secure?