R1#SH RUN | b interface Tun
interface Tunnel0
 no ip address
 no ip redirects
 ipv6 address 2002:B428:742::1/128
 ipv6 rip RipR1 enable
 tunnel source Ethernet0/0
 tunnel mode ipv6ip 6to4
!
interface Ethernet0/0
 ip address 180.40.7.66 255.255.255.224
 half-duplex
!

ipv6 route 2002::/16 Tunnel0
ipv6 route ::/0 2002:B428:701::7


R7#sh run | b interface Tun
interface Tunnel0
 no ip address
 no ip redirects
 ipv6 address 2002:B428:701::7/128
 ipv6 rip RipR7 enable
 tunnel source FastEthernet0/1
 tunnel mode ipv6ip 6to4

!
interface FastEthernet0/1
 ip address 180.40.7.1 255.255.255.224
 duplex auto
 speed auto
!

!
ipv6 route 2002::/16 Tunnel0
ipv6 route ::/0 2002:B428:742::1