I have configured my tunnel using aiccu on my FreeBSD router machine. It has an external WAN interface xl0 and an internal LAN interface fxp0. The tunnel is active and working correctly from the internet to the WAN interface of the router. Internet hosts can ping the machine and the machine can ping other IPv6 hosts on the internet. I have enabled rtadvd on the gateway/router machine, and another FreeBSD host on the LAN has autoconfigured itself. The LAN host is able to ping the inet6 address of fxp0 and the gateway/router machine is able to ping the autoconfigured inet6 address of the LAN host. The problem is that the FreeBSD router is not routing the traffic. Internet hosts cannot ping the autoconfigured address of the LAN host and the LAN host cannot ping the tunnel client endpoint address on xl0 nor any other addresses that would require the router to forward traffic. I use pf for filtering. Is there some rule that pf requires to allow simple routing (forwarding) of IPv6 traffic between connected interfaces? NAT is working for IPv4 already.