For Google Fiber they just provide a PON jack with an ethernet port. They do not use PPPoE. As long as the VLAN and egress COS bit are set, the service will function and provide a DHCP address to the WAN interface.
I tried to get IPFire up and running using the vconfig syntax in the link above but I did not have any luck. I went back to testing in a VM to see if I can get the COS bit set but so far, the commands I am running do not seem to have an effect. It’s also possible that the old thread I am referencing is using a deprecated command and maybe I need to be using a newer method?
I know that setting the COS bit is needed because I can use other firewalls that support this and the service fires up immediately. I think it’s just the missing COS bit on IPFire that is preventing it from working. I’m happy to try to test pilot this too and determine a good solution to get IPFire working.