Unfortunately CenturyLink provisions their fiber to the home with a PPPoE authentication over vlan 201, this makes replacing the router more difficult than it should be. I also had to call CenturyLink support to get the password for the PPPoE connection.
cnmac0 is the egress interface on my EdgeRouter Lite.
You also need to add match on pppoe0 scrub (max-mss 1452)
to your pf.conf because otherwise many things don't work. (Thanks Bryan) Specifically, 40 less than the mtu on pppoe0.
If you're doing ipsec over this link, you also need to scrub the enc0 max-mss to 64 smaller than the max-mss on the pppoe interface. match on enc0 scrub (max-mss 1428)
.
Overall it ends up being fairly forward, the PPPoE config is copied directly from the man page with the minor change that CenturyLink uses chap instead of pap.
The IPv6 setup was based on these resources from some DuckDuckGo.com searches
I've used tpmr(4) to snoop the traffic between the ISP router and their service to figure out what's going on before, like what VLANs are in use, pppoe or not, or pppoe creds.