R1#sh run | b router
!
ipv6 router rip R1Rip
  distribute-list prefix-list NoR4Loop out Serial0/1
!
!
!
ipv6 prefix-list NoR4Loop seq 5 deny 2000:4:4::/64
ipv6 prefix-list NoR4Loop seq 10 permit ::/0 le 128
!