Cisco1111 DHCPv6 Client - Prefix Delegation

[jannisbshs]

Hi all,

I am trying to get my C1111-4PLTEEA to act as a DHCPv6 client with PD.
This is what my interface config looks like:

interface GigabitEthernet0/0/0
ip address dhcp
media-type rj45
negotiation auto
ipv6 address dhcp
ipv6 enable
ipv6 nd autoconfig prefix
ipv6 nd autoconfig default-route
ipv6 dhcp client pd PREFIX

I am receiving an IP-Adress from the DHCP Server, but the delegated Prefix doesn't show up under "show ipv6 dhcp interface".
It seems like the router keeps trying to ask for a delegated prefix, but I am gettting this log message each time:
IPv6 DHCP: No matching transaction ID in ADVERTISE from FE80::B2F2:8FF:FE02:7ACA on GigabitEthernet0/0/0
When looking at the packets in Wireshark, I can't find a problem wirh the transaction ID. It's exactly the same as in the SOLICIT message.
Am I missing something here?

Thanks in advance

[Harold Ritter]

Hi @jannisbshs ,

Here's a few recommendations about the interface configuration:

interface GigabitEthernet0/0/0
ipv6 address dhcp
no ipv6 nd autoconfig prefix <+++++ you do not want SLAAC to be performed by the router

ipv6 nd ra suppress <++++ You want to suppress the RA on this interface
ipv6 nd autoconfig default-route
ipv6 dhcp client pd PREFIX rapid-commit <+++ the rapid-commit normally helps

Can you please provide the "show ipv6 dhcp interface" output after making these changes.

Regards,

[jannisbshs]

Hi @Harold Ritter ,

Here is my adjusted interface config:

interface GigabitEthernet0/0/0
ip address dhcp
media-type rj45
negotiation auto
ipv6 address dhcp
ipv6 enable
ipv6 nd autoconfig default-route
ipv6 nd ra suppress
ipv6 dhcp client pd PREFIX rapid-commit
end

Unfortunately, the behavior regarding the prefix delegation is the same.

This ist what the output of "show ipv6 dhcp interface" looks like:

GigabitEthernet0/0/0 is in client mode
Prefix State is REQUEST (6)
Retransmission timer expires in 00:00:21
Address State is OPEN
Renew for address will be sent in 00:29:21
List of known servers:
Reachable via address: FE80::B2F2:8FF:FE02:7ACA
DUID: 00030001B0F208027ACA
Preference: 0
Configuration parameters:
IA NA: IA ID 0x00050001, T1 1800, T2 2880
Address: XXXX::XXXX/128
preferred lifetime 3600, valid lifetime 7200
expires at Mar 16 2023 12:32 PM (7162 seconds)
DNS server: FD00::B2F2:8FF:FE02:7ACA
Information refresh time: 0
Prefix name: PREFIX
Prefix Rapid-Commit: enabled
Address Rapid-Commit: disabled

I can definitely see that my IAD is handing the cisco router a prefix, but for some reason it won't accept the Reply message

Mar 16 16:48:44.595: option IA-PD(25), len 41
Mar 16 16:48:44.595: IAID 0x00050001, T1 1800, T2 2880
Mar 16 16:48:44.595: option IAPREFIX(26), len 25
Mar 16 16:48:44.595: preferred 3600, valid 7200,
 prefix XXXX:908:1426:DA9C::/62
Mar 16 16:48:44.595: IPv6 DHCP: No matching transaction ID in REPLY from FE80::B2F2:8FF:FE02:7ACA on GigabitEthernet0/0/0

Thanks and regards,

Jannis

[Harold Ritter]

Hi @jannisbshs ,

Thanks for the additional information. Can you please post the "show version" output.

Regards,