I have 2 routers from the same ISP but different public IP that works with PPPoE and I need to connect both into the same firewall (Watchguard). Both PPPoE have the same user, password and VLAN, so I don't know how to do it. I tried to configure a switch with 2 access ports with different vlan (6 and 7) and a trunk port with both vlan tagged. The firewall port has both vlan tagged to and the pppoe configuration is correct, but I'm unable to get the public IP on the firewall interfaces with this configuration. Maybe PPPoE cannot be configured into tagged vlan or a trunk port?
This is the de schema:
And this is what I get into the Watchguard interface status: