ip forwarding
ipv6 forwarding

int eth-dummy
 ip addr 172.16.6.6/24
 ip addr fd00:600::6/64

int eth-rr
 ip addr 192.168.4.6/24
 ipv6 address fd00:0:4::6/64

int lo
 ip addr 10.6.6.6/32
 ipv6 address 2001:db8::6/128