! interface Ethernet0 mtu 1512 no ip address ! interface Ethernet0.101 encapsulation dot1Q 101 pppoe-client dial-pool-number 1 pppoe-client ppp-max-payload 1500 !
You may have a different pool number so change as required.
However, the 867 isn't supported for native FTTC and I often have crashes and upstream issues. You can configure the router for ethernet WAN mode and use a VDSL modem if you have one. Just add the following instead:
wan mode ethernet
no shut no ip address ip mtu 1492 duplex auto speed auto pppoe-client dial-pool-number 1