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Advanced statistics

JunOS 8.3 and higher support IPv6 statistics. To enable:

forwarding-options {
   family inet6 {

To display the statistics, use the show interface statistics command in operational mode.

DHCPv6 configuration

This example configuration directs client not to perform stateless autoconfiguration (RFC 2462). Instead they are directed to request an address and configuration data from a DHCPv6 server.

protocols {
	router-advertisement {
		interface ge-0/1/0.0 {
		    managed-configuration;		<--- sets the M bit in the RA
		    other-stateful-configuration;	<--- sets the O bit in the RA
		    prefix 2001:0DB8:10:4::/64 {
			no-autonomous;                  <--- disable stateless auto-config

Cisco IOS

Cisco has a table listing IPv6 features by IOS version.

You may need to upgrade your supervisor card(s) to one capable of routing IPv6 in hardware. On the 4500 series, you need to run a Sup 6-E or 6L-E. The Sup V supports IPv6 in software. On the 6500, a Sup 32 or Sup 720 is required for IPv6 hardware routing. A Sup 2 is capable of routing in IPv6 in software.

This will briefly describe how to get IPv6 routing working under Cisco's IOS. Not covered are ipv6 in access-lists and disabling stateless autoconfig.

You need to be running an "Advanced IP Services" image. This example is based on configuring a Cisco 3750G-24TS running 12.2(44)SE2. Update: As of IOS 12.2(50)SE, IPv6 support is included in IP Base.

Also for this example, we have the following

  • IPv6 Global subnet (assigned to us by TNS): 2610:8:7800:14::/64
  • IPv6 ULA between our router and TNS: fd0b:7cdb:aefd:6c06::/64
  • IPv6 ULA on TNS's router: fd0b:7cdb:aefd:6c06::1
  • IPv6 ULA on our router: fd0b:7cdb:aefd:6c06::2

Change SDM

If you just upgraded to an image with the Advanced IP Services, you will need to change the SDM (Switch Database Management) template. To see what template you are currently using:

> enable
# show sdm prefer
 The current template is "desktop IPv4 and IPv6 routing" template.
 The selected template optimizes the resources in
 the switch to support this level of features for
 8 routed interfaces and 1024 VLANs. 

  number of unicast mac addresses:                  1.5K
  number of IPv4 IGMP groups + multicast routes:    1K
  number of IPv4 unicast routes:                    2.75K
    number of directly-connected IPv4 hosts:        1.5K
    number of indirect IPv4 routes:                 1.25K
  number of IPv6 multicast groups:                  1.125k
  number of directly-connected IPv6 addresses:      1.5K
  number of indirect IPv6 unicast routes:           1.25K
  number of IPv4 policy based routing aces:         0.25K
  number of IPv4/MAC qos aces:                      0.75K
  number of IPv4/MAC security aces:                 0.5K
  number of IPv6 policy based routing aces:         0.25K
  number of IPv6 qos aces:                          0.5K
  number of IPv6 security aces:                     0.5K

If you do not see anything about IPv6, you will have to switch to a template that includes IPv6:

(you will have to reload the switch for changes to the sdm to take effect)

# configure terminal
(config)# sdm prefer dual-ipv4-and-ipv6 [default|routing|vlan|desktop]
(config)# end
# reload

After the reload, you should now have the ipv6 command.

Configure ULA on TNS side of router

Let's first add the ULA that TNS gave us to our outside interface:

# configure terminal
(config)# interface GigabitEthernet1/0/1
(config)# ipv6 address fd0b:7cdb:aefd:6c06::2/64
(config)# end

Verify that it is configured:

> show ipv6 interface GigabitEthernet1/0/1
GigabitEthernet1/0/1 is up, line protocol is up
  IPv6 is enabled, link-local address is FE80::20D:29FF:FE75:60C1
  Global unicast address(es):
    FD0B:7CDB:AEFD:6C06::2, subnet is FD0B:7CDB:AEFD:6C06::/64
  Joined group address(es):
  MTU is 1500 bytes
  ICMP error messages limited to one every 100 milliseconds
  ICMP redirects are enabled
  Output features: Check hwidb
  ND DAD is enabled, number of DAD attempts: 1
  ND reachable time is 30000 milliseconds
  ND advertised reachable time is 0 milliseconds
  ND advertised retransmit interval is 0 milliseconds
  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.

Enable IPv6 routing

Next, enable IPv6 routing, and set the default route to TNS's interface:

# configure terminal
(config)# ipv6 unicast-routing
(config)# ipv6 route ::/0 fd0b:7cdb:aefd:6c06::1
(config)# end

Configure default gateway on internal interface

Finally, add an IPv6 address to your internal interface to be used as the default gateway, in this case, Vlan1:

# configure terminal
(config)# interface Vlan1
(config)# ipv6 address 2610:0008:7800:0014::1/64
(config)# end

That should do it.

DHCPv6 Configuration

To enable the M and O flags in the Router Advertisement, and to disable stateless autoconfig (the A flag):

Router1(config)# interface FastEthernet0/0
Router1(config-if)# ipv6 nd managed-config-flag
Router1(config-if)# ipv6 nd other-config-flag
Router1(config-if)# ipv6 nd prefix default no-autoconfig
Router1(config-if)# exit

See the Cisco IPv6 Command Reference for specifics on the ipv6 nd managed-config-flag, ipv6 nd other-config-flag, and ipv6 prefix commands.


VRRP does not yet support IPv6. A revised VRRP draft is in last call in the IETF.

JunOS implemented an earlier draft of VRRP-ipv6 in JunOS 8.4. Support was improved in 9.1 to use the virtual router link-local address in the RA.

Cisco's HSRP supports IPv6 as of IOS 12.2(33)SXI (relnotes) on Catalyst 6500, and 12.2(50)SE (relnotes) on the Catalyst 3560/3750.