Basic configuration IPv6 Cisco IOS

Enabling IPv6 Globally

Start the IPv6 routing process and allow IPv6 CEF switching.

Router(config)#<input>ipv6 unicast-routing</input>
Router(config)#<input>ipv6 cef</input>

Configuring IPv6 address on interface

R3(config)#<input>int fa0/0</input>
R3(config-if)#<input>ipv6 enable</input>
R3(config-if)#<input>ipv6 address 2001:16D8:DD85:139::7/64</input>
R3(config-if)#<input>exit</input>
R3(config)#<input>int fa0/1</input>
R3(config-if)#<input>ipv6 enable</input>
R3(config-if)#<input>ipv6 address 2001:16D8:DD85:140::1/64</input>
R3(config-if)#<input>ipv6 dhcp relay destination 2001:16D8:DD85:4::166</input>

Showing IPv6 configuration on interface

R3#<input>show ipv6 int fa0/0</input>
FastEthernet0/0 is up, line protocol is up
  IPv6 is enabled, link-local address is FE80::128C:CFFF:FE2E:916E
  No Virtual link-local address(es):
  Global unicast address(es):
    2001:16D8:DD85:139::7, subnet is 2001:16D8:DD85:139::/64
  Joined group address(es):
    FF02::1
    FF02::2
    FF02::1:FF00:7
    FF02::1:FF2E:916E
  MTU is 1500 bytes
  ICMP error messages limited to one every 100 milliseconds
  ICMP redirects are enabled
  ICMP unreachables are sent
  ND DAD is enabled, number of DAD attempts: 1
  ND reachable time is 30000 milliseconds (using 30000)
  ND advertised reachable time is 0 (unspecified)
  ND advertised retransmit interval is 0 (unspecified)
  ND router advertisements are sent every 200 seconds
  ND router advertisements live for 1800 seconds
  ND advertised default router preference is Medium
  Hosts use stateless autoconfig for addresses.

Default IPv6 Unicast Route

Notice the 2000::/3 prefix which identifies the total IPv6 Unicast area. The next-hop IPv6 address 2001:16D8:DD85:4::1 should - as in IPv4 - be on a local attached subnet.

R3(config)#<input>ipv6 route 2000::/3 2001:16D8:DD85:139::1</input>

Showing IPv6 Route table

S   2000::/3 [1/0]
     via 2001:16D8:DD85:139::1
C   2001:16D8:DD85:139::/64 [0/0]
     via FastEthernet0/0, directly connected
L   2001:16D8:DD85:139::7/128 [0/0]
     via FastEthernet0/0, receive
C   2001:16D8:DD85:140::/64 [0/0]
     via FastEthernet0/1, directly connected
L   2001:16D8:DD85:140::1/128 [0/0]
     via FastEthernet0/1, receive
L   FF00::/8 [0/0]
     via Null0, receive