Hello Jus1. Thanks for posting your question here. Yes, we do utilize DHCP for both IPv4 and IPv6 addresses. Our support for 3rd party routers is limited, but if you have already rebooted the modem and router before attempting to re-pull the IPv6 address I would recommend a direct connection to the modem to verify it comes through for you. Be sure to reboot or power off the equipment between device changes.