hostname r4 interface r4-eth0 ip address 10.0.21.1/24 ipv6 address 2001:db8:1:2::1/64 ! interface r4-eth1 ip address 10.0.11.2/24 ipv6 address 2001:db8:2:2::2/64 ! interface lo ip address 10.254.0.4/32 ipv6 address 2001:db8:F::4/128 !