How to configure EUI-64 based Global Unicast IPv6 Address in a Cisco Router Interface

Global Unicast IPv6 Addresses are globally routable addresses on IPv6 Internet. Currently left most three bits of Global Unicast IPv6 Addresses are fixed as 001. Therefore, the range of Global Unicast Addresses available now are from 2000 to 3FFF. Please visit Global Unicast IPv6 Addresses for more details. We can assign a Global Unicast IPv6 Addresses to an interface using different ways. Please visit the below link to learn more about different methods to assign a Global Unicast IPv6 address to an interface.

EUI-64 based Global Unicast IPv6 addresses are also a type of auto-configured Global Unicast IPv6 Addresses. As defined in RFC 4291, IPv6 generates a 64-bit interface part (host part) of the Global Unicast IPv6 Address from the interface MAC address. The EUI-64 method of generating a Global Unicast IPv6 Address involves selecting the 6-byte (48-bit) interface MAC address and the and then generating a Global Unicast IPv6 Address by expanding it into a 64-bit interface part (host part).

Click the following link to learn more about EUI-64 based Global Unicast IPv6 Address and how EUI-64 Global Unicast IPv6 are generated from interface MAC address.

Following Cisco IOS configuration commands can be used to configure an EUI-64 based Static Global Unicast IPv6 Address in a Cisco Router Interface.

OmniSecuR1#configure terminal
OmniSecuR1(config)#int fastEthernet 0/0
OmniSecuR1(config-if)#ipv6 address 2001:db8:aaaa:1::/64 eui-64
OmniSecuR1(config-if)#no shutdown
OmniSecuR1(config-if)#exit
OmniSecuR1(config)#exit
OmniSecuR1#

After configuring the EUI-64 based Global Unicast IPv6 address, you can view the interface status using the Cisco IOS show command "show ipv6 interface brief" as shown below.

OmniSecuR1#show ipv6 interface brief
FastEthernet0/0            [up/up]
    FE80::C800:CFF:FEF0:8
    2001:DB8:AAAA:1:C800:CFF:FEF0:8
FastEthernet0/1            [administratively down/down]

The MAC address of the interface is "ca00.0cf0.0008". Visit the following lesson EUI-64 based Global Unicast IPv6 and calculate yourself how the IPv6 address 2001:DB8:AAAA:1:C800:CFF:FEF0:8 is autoconfigured.