R1#sh run | b 0/1
interface Ethernet0/1
 no ip address
 half-duplex
 ipv6 address 2005:0:104::/64 eui-64
 ipv6 rip R1RIP enable
!
interface Serial0/1
 no ip address
 ipv6 address 2005:0:102::/64 eui-64
 ipv6 rip R1RIP enable
 clock rate 64000
!
!
ipv6 router rip R1RIP
!
!
!
!

R2#sh run | b 1/1
interface Serial1/1
 no ip address
 ipv6 address 2005:0:102::/64 eui-64
 ipv6 rip R2RIP enable
!

R4#sh run | b Lo
interface Loopback0
 no ip address
 ipv6 address 2000:4:4::/64
 ipv6 rip R4RIP enable
!
interface FastEthernet0/0
 no ip address
 duplex auto
 speed auto
 ipv6 address 2005:0:104::/64 eui-64
 ipv6 rip R4RIP enable
!