Cisco Routers and IPv6 Networking

Posted on 2013-06-09
Last Modified: 2013-06-29
Say I have 2 routers, 2901 models with just the fast ethernet interfaces in them.
I am wanting to simulate WAN connections between sites. These sites are just theoretical at this time.

Interface FastEthernet 0/0 on Router 1 is given an IPv6 address of 2001:0:1:1::1/64
Router1(Config-if)# ipv6 address 2001:0:1:1::1/64

Interface FastEthernet 0/0 on Router 2 is given an IPv6 address of 2001:0:1:1::2/64
Router2(Config-if)# ipv6 address 2001:0:1:1::2/64

I have enabled dynamic routing on the interfaces using the following commands:
Router1(Config)# ipv6 router rip company
Router1(Config)# interface fastethernet 0/0
Router1(Config-if)# ipv6 rip company enable
Router1(Config-if)# exit

Router2(Config)# ipv6 router rip company
Router2(Config)# interface fastethernet 0/0
Router2(Config-if)# ipv6 rip company enable
Router2(Config-if)# exit

I have IPv4 addresses assigned to the FastEthernet 0/1 interfaces on both routers

Router1# config t
Router1(Config)# interface fastethernet 0/1
Router1(Config-if)# ip address
Router1(Config-if)# no shutdown
Router1(Config-if)# end

Router2# config t
Router2(Config)# interface fastethernet 0/1
Router2(Config-if)# ip address
Router2(Config-if)# no shutdown
Router2(Config-if)# end

On each router, I can ping the WAN interface of the other. I cannot ping the internal IPv4 address from the opposite router. I am looking for a way to allow communication between the two networks. Perhaps a NAT64 entry would work best, or perhaps a static route.

Does anyone have a command I could run on both routers to allow a PC on Router 1's Fast Ethernet 0/1 interface to ping and communicate directly with a PC on Router 2's Fast Ethernet 0/1 interface?

Example config's are welcome, I'll keep trying but I am looking to speed up this process.
Question by:PatrickDoman
  • 2

Expert Comment

by:Sandeep Gupta
ID: 39234156
Here is good exmple config from cisco to work together with IPV4 & IPV6

Good luck
LVL 22

Expert Comment

by:Jody Lemoine
ID: 39234182
IPv6 routing is disabled by default on IOS. Enable it with the command "ipv6 unicast-routing" and things should start working as expected.

Accepted Solution

PatrickDoman earned 0 total points
ID: 39272524
Here was the fix for the proof of concept. Works great!

Network topology:- - Router1 - (IPv6) - Router2 -


interface Tunnel1
ip address
tunnel source 2001:0:1:1::1
tunnel destination 2001:0:1:1::2
tunnel mode ipv6

ip route Tunnel1


interface Tunnel1
ip address
tunnel source 2001:0:1:1::2
tunnel destination 2001:0:1:1::1
tunnel mode ipv6
ip route Tunnel1

Author Closing Comment

ID: 39286404
Cisco TAC engineer helped me through this. Works fine. Was able to ping machines on both sides of the routers.

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