How to Configure IPv6 on Cisco Router Examples

By | 9th November 2015

Enabling IPv6 on Cisco Routers.

By default, IPv6 traffic-forwarding is disabled on a Cisco router. It must be activated between interfaces by using the global configuration command  – ipv6 unicast-routing. The global configuration command must be used in both Stateful (DHCPv6) and Stateless autoconfiguration.

There are two basic steps used to activate IPv6 on a Cisco router:

i.        First, you must activate IPv6 traffic-forwarding on the router, and

ii.       then you must configure each interface that requires IPv6.

Command syntax for enabling IPv6 on Cisco routers:

Enabling IPv6 on Cisco Routers.

When a network router interface is configured with an ipv6 address, a link-local address will be configured automatically for the interface.

You must specify the entire 128-bit IPv6 address or specify to use the 64-bit prefix by using the eui-64 option.

IPv6 Address Configuration Example

ipv6 config

From the above IPv6 address configuration example,  router1 is shown connected to an IPv6 WAN to router2 with a subnet prefix address of 2001:db8:3c4d:2::/64.

We used the following commands:

R1(config)#ipv6 unicast-routing     ( configure the router to activate IPv6 routing and configure the router fa0/1 interface).

The EUI-64 option is used to create the 64-bit MAC address.


The MAC address of the Ethernet Fa0/1 interface is 0260.3d47.1720.

Using the show ipv6 interface fa0/1 command, the MAC address is displayed as part of the IPv6 address with the Hex characters FFFE (16 bits) added in the middle, which expands the 48-bit MAC address to create the IPv6 64-bit link-local address.

R1#show ipv6 interface fa0/1

Fa0/1 is up, line protocol is up

IPv6 is enabled, link-local address is FE80::260:3dFF:FE47:1720

Global unicast addresses:

2001:DB8:C18:1:260:3EFF:FE47:1720, subnet is 2001:DB8:C18:1::/64

Joined group addresses:




MTU is 1500 bytes

How IPv6 address is formed.

ipv6 config2

Why We Need IPv6.

IPv6 Address Expression and Examples.

Types of IPv6 Address

IPv6 Routing Protocols.

Ways To Migrate To IPv6

How to Configure IPv6 Static and Default Routes.

Host Standby Router Redundancy Protocol (HSRP)

Virtual Router Redundancy Protocol (VRRP)

Gateway Load Balancing Protocol (GLBP)

Spanning Tree Protocol (STP)

VLAN Trunking Protocol (VTP)


RIPv6 or RIPng



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