Configuring OSPF for IPv6 on Cisco IOS

1. Enable IPV6:

R4(config)# ipv6 unicast-routing

2. Supply interface fa0/0 with an IPV6 address:

R4(config-if)# ipv address 2001:0:0:1::/64 eui-64

3. Configure an IPV6 OSPF routing process 110:

R4(config)# ipv6 router ospf 110 
Here manually supply a router id: (optional if ipv4 addresses are present)
R4(config-rtr)# router-id

 4. Enable IPV6 OSPF on the IF fa0/0:
R4(config-if)# ipv6 ospf 110 area 0
R4(config-if)# do sh ipv6 protocols
IPv6 Routing Protocol is "connected"
IPv6 Routing Protocol is "static"
IPv6 Routing Protocol is "ospf 110"
  Interfaces (Area 0):

Perform the tasks above on the adjacent router as well and check whether an OSPF adjacency is formed.

R4(config-if)# do sh ipv6 ospf neighbor

Neighbor ID Pri State Dead Time Interface ID Interface 1 FULL/BDR 00:00:36 4 FastEthernet0/0

5. Add a fictional IPV6 network on a loopback interface:

R4(config-if)# int lo0

R4(config-if)# ipv6 address 2001:0:0:2::/64 eui-64

Enable OSPF-6 on this interface:

R4(config-if)# ipv6 ospf 110 area 0

Perform these tasks on the adjacent router as well with a different IPV6 network on the loopback interface, eg 2001:0:0:3::/64.

Check the IPV6 addresses on the NIC’s:

R4# sh ipv6 int brief

FastEthernet0/0 [up/up]



FastEthernet0/1 [administratively down/down]

Loopback0 [up/up]



Check the OSPF-6 route distribution:

R4# sh ipv6 route

O 2001::3:C603:40FF:FEA2:0/128 [110/10]

via FE80::C603:40FF:FEA2:0, FastEthernet0/0

Notice the /128: this is the route to 1 IP address, since OSPF recognizes the nature of the loopback address. (1 address, not a whole network)

6. Test the route

Hint : at this stage, to see the adjacent IPV6 address, “show cdp neighbours detail” is your friend in identifiying those tiresome IPV6 addresses.

R4# traceroute 2001::3:C603:40FF:FA2:0

Type escape sequence to abort.

Tracing the route to 2001::3:C603:40FF:FEA2:0

1 2001::3:C603:40FF:FEA2:0 16 msec 20 msec 24 msec

Configuring OSPF MD5 Authentication

The following example defines authentication on the Ethernet 0/0 interface:

R4(config-if)#ipv6 ospf authentication ipsec spi 256 md5 0 1234567890ABCDEF1234567890ABCDEFat this stage the OSPF neighbour relation is temporarily lost as long as the authentication has not been setup on both adjacent routers.32 characters are needed here for MD5

Configure this on the adjacent router as well. 
The adjacency relationship should be restore and all is jolly.
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