DHCPv6 Relais Agent no auto static route for prefix delegation

[POM-Fr]

Hello,

In order to deploy IPv6 on an infrastructure I realize different labs.

The objective of one of my labs is to set up a DHCPv6 relay on a cisco 2921 router to see how it reacts with the distribution of a prefix delegation.

In the documentation I read, the IPv6 DHCPv6 Relay Agent Notification feature is supposed to create a static route in the router's routing table when the router receives a DHCPv6 RELAY-REPLY. Here is the exact sentence:

"No user configuration is required for this feature. Static route management is done automatically by the relay agent."

However, on my lab no roads are automatically added. Here is my configuration:

Here is my configuration on R1:

interface GigabitEthernet0/0.950
 encapsulation dot1Q 950
 no ip proxy-arp
 ipv6 address FE80::950:2 link-local
 ipv6 address 2001:DB8:67:950::950:2/64
 ipv6 enable
 ipv6 nd managed-config-flag
 no ipv6 redirects
 ipv6 dhcp relay destination 2001:DB8:67:951::951:10
 ipv6 virtual-reassembly in
end
!
interface GigabitEthernet0/0.951
 encapsulation dot1Q 951
 no ip proxy-arp
 ipv6 address FE80::951:2 link-local
 ipv6 address 2001:DB8:67:951::951:2/64
 ipv6 virtual-reassembly in
end

The R2 router receives an IPv6 address on its WAN interface with a prefix delegation but no route to this prefix is created on R1.

Does anyone had an idea?

Best regards,

POM

[Deepak Kumar]

Hi,

Please note that:

IPv6 routes are added when the relay agent relays a RELAY-REPLY packet, and IPv6 routes are deleted when the prefix delegation lease time expires or the relay agent receives a release message. An IPv6 static route in the routing table of the relay agent can be updated when the prefix delegation lease time is extended.

[POM-Fr]

Hi Deepak kumar,

I totaly agreed withs this fact. In my situation this is exactly what happens but no routes are added, the DHCPv6 server send a RELAY-REPLY to R1 (the relay agent) with the IPv6 prefix and R1 sends it to R2.

When I enable the ipv6 dhcp debug on R1, I see RELAY-REPLY messages passing by. So I don't understand why no roads are added.

Regards,

POM