How to send reconfigure messages from DHCPv6 Server to DHCPv6 Client?

[mzk_murata]

I set up DHCPv6 Server in my lab and I'd like to send reconfigure messages from DHCPv6 Server to DHCPv6 Client.
Please instruct me how to send reconfigure messages from DHCPv6 Server to DHCPv6 Client.

There is a post about "Implementing DHCPv6 - An Introduction".
(https://community.cisco.com/t5/networking-blogs/implementing-dhcpv6-an-introduction/ba-p/3106104)

And there is an explanation about "Reconfigure Message".
It says "The Reconfigure Message is sent by the DHCPv6 server to the client when the server has new or updated information of configuration parameters. It tells the client to initiate a information-request/reply message to the server so as to receive the updated information."

I added "debug ipv6 dhcp detail" command and I watched logs. but no reconfigure message is sent from my DHCPv6 Server.

I also change dns-server/sntp **bleep** option. but no reconfigure message is sent from my DHCPv6 Server

Is there any ways to send reconfigure messages?

---configuration(exemption) for my DHCPv6 Server-------------------
!
version 15.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname DHCPServer01
!
boot-start-marker
boot-end-marker
!
!
no logging console
enable secret 5 XXXXXXX
!
no aaa new-model
clock timezone JST 9 0
!
!
no ip domain lookup
ip cef
ipv6 unicast-routing
ipv6 cef
ipv6 dhcp pool DHCP-1
prefix-delegation pool dhcpv6-pool1 lifetime 1800 600
dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2
!
ipv6 dhcp pool DHCP-2
prefix-delegation pool dhcpv6-pool2 lifetime 1800 600

dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2
!
ipv6 dhcp pool DHCP-3
prefix-delegation pool dhcpv6-pool3 lifetime 1800 600

dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2
!
ipv6 dhcp pool DHCP-4
prefix-delegation pool dhcpv6-pool4 lifetime 1800 600

dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2
!
!
interface BRI0
no ip **bleep**
encapsulation hdlc
shutdown
isdn termination multidrop
!
interface FastEthernet0
no ip **bleep**
shutdown
duplex auto
speed auto
!
interface GigabitEthernet0
switchport access vlan 10
no ip **bleep**
!
interface GigabitEthernet1
switchport access vlan 20
no ip **bleep**
!
interface GigabitEthernet2
switchport access vlan 30
no ip **bleep**
!
interface GigabitEthernet3
switchport access vlan 40
no ip **bleep**
!
interface GigabitEthernet4
no ip **bleep**
!
interface GigabitEthernet5
no ip **bleep**
!
interface GigabitEthernet6
no ip **bleep**
!
interface GigabitEthernet7
no ip **bleep**
!
interface GigabitEthernet8
no ip **bleep**
duplex auto
speed auto
ipv6 **bleep** 2001:0:0:1000::1/64
ipv6 rip r1 enable
!
interface Vlan1
no ip **bleep**
!
interface Vlan10
no ip **bleep**
ipv6 **bleep** FE80::1 link-local
ipv6 **bleep** 2001:410:0:1000::1/64
ipv6 enable
ipv6 nd managed-config-flag
ipv6 nd other-config-flag
ipv6 dhcp server DHCP-1
ipv6 rip r1 enable
!
interface Vlan11
no ip **bleep**
!
interface Vlan20
no ip **bleep**
ipv6 **bleep** FE80::1 link-local
ipv6 **bleep** 2001:420:0:1000::1/64
ipv6 enable
ipv6 nd managed-config-flag
ipv6 nd other-config-flag
ipv6 dhcp server DHCP-2
ipv6 rip r1 enable
!
interface Vlan30
no ip **bleep**
ipv6 **bleep** FE80::1 link-local
ipv6 **bleep** 2001:430:0:1000::1/64
ipv6 enable
ipv6 nd managed-config-flag
ipv6 nd other-config-flag
ipv6 dhcp server DHCP-3
ipv6 rip r1 enable
!
interface Vlan40
no ip **bleep**
ipv6 **bleep** FE80::1 link-local
ipv6 **bleep** 2001:440:0:1000::1/64
ipv6 enable
ipv6 nd managed-config-flag
ipv6 nd other-config-flag
ipv6 dhcp server DHCP-4
ipv6 rip r1 enable
!
interface Vlan100
no ip **bleep**
!
interface Async3
no ip **bleep**
encapsulation slip
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
ipv6 local pool dhcpv6-pool1 2001:410:0:1000::/56 60
ipv6 local pool dhcpv6-pool2 2001:420:0:1000::/56 60
ipv6 local pool dhcpv6-pool3 2001:430:0:1000::/56 60
ipv6 local pool dhcpv6-pool4 2001:440:0:1000::/56 60
ipv6 router rip r1
!
!
---------------------------------------------------------

[Rich R]

Just because the reconfigure option exists doesn't mean that Cisco IOS DHCP server supports it.  The IOS DHCP server has limited functionality compared to a full featured DHCP server product.  For example:
https://www.cisco.com/c/en/us/td/docs/routers/asr920/configuration/guide/ipaddr-dhcp/17-1-1/b-dhcp-xe-17-1-asr920/b-dhcp-xe-17-1-asr920_chapter_0101.html
"DHCPv6 Reconfigure message type is not be supported on the Cisco ASR920 Series routers."

Maybe you could use the minimum refresh interval to trigger the update from the client side:
https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr/command/ipaddr-cr-book/ipaddr-i4.html#wp3729878849

[mzk_murata]

Hi, Rich R

That is really helpful.
I'll try to set the minimum refresh interval for DHCPv6 clients.

I really appreciate your help.
Thanks a lot!

[Harold Ritter]

Hi @mzk_murata ,

I completely agree with what @Rich R wrote about the fact that the reconfigure message might not be supported on all platforms.

One thing I noticed though is that you basic DHCPv6 configuration is not right. You configured the server as a DHCPv6 prefix delegation (PD) server. That is probably not what you want. If you want the hosts to get IPv6 addresses, you should use the following configuration instead.

ipv6 dhcp pool DHCP-1
address prefix 2001:410:0:1000::/64 lifetime infinite infinite
dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2

!

ipv6 dhcp pool DHCP-2
address prefix 2001:420:0:1000::/64 lifetime infinite infinite

dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2
!
ipv6 dhcp pool DHCP-3
address prefix 2001:430:0:1000::/64 lifetime infinite infinite

dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2
!
ipv6 dhcp pool DHCP-4
address prefix 2001:440:0:1000::/64 lifetime infinite infinite

dns-server 2001:500:0:1000::1
sntp **bleep** 2001:500:0:1000::2
!

Regards,