[Kea-users] Kea 1.6 DHCP6 configuration on Raspberry Pi 3b running Ubuntu 20.04

russell aspinwall raspinwall at willows7.myzen.co.uk
Tue Mar 2 13:56:58 UTC 2021


Hi

Problem resolved, on Linuxmint 20 configuring IPv6 as automatic, 
addresses only results in the client obtaining an IPv6 address which is 
::/128, however it is possible to ping6 any device in the ::/64 subnet. 
Thanks for pointing out about what should be learnt from RA rather than 
DHCP. I mistakingly thought RA was only used to indicate that DHCP was 
to be used.

Thanks

Russell

On 02/03/2021 11:35, russell aspinwall wrote:
> Hi
>
> 95% of the devices have fixed IPv4 and IPv6 addresses and are working 
> perfectly. DHCPv4 is also working perfectly for the small number of 
> devices that need it.
> DHCPv6 is working, clients are being assigned an IP address from the 
> correct pool but with a ::/128 address but are unable to communicate 
> with any other IPv6 device on the network.
>
> I have used wireshark to capture the RA from the pfsense firewall
>
> ICMPv6
>      Managed address configuration: Set
>      Other Configuration : Set
>      Home Agent : Not Set
>      Prf (Default Router Preference): Medium (0)
>      Proxy : Not Set
>      Reserved : 0
>         ICMPv6 Option (Prefix information  :   NNNN::/64 )        
> subnet is correct
>         ICMPv6 Option (Route Information : Medium    ::/0)
>         ICMPv6 Option (Recursive DNS Server    NNNN:::AAAA) dns server 
> is correct
>         ICMPv6 Option (DNS Search List Option  euclid.plato ) dns 
> search is correct
>         ICMPv6 Option (MTU :1492)
>         ICMPv6 Option (Source link-layer :  pfsense LAN mac)
>
> What I am missing that is stopping the DHCPv6 (Linuxmint 20) from 
> correctly assigning the ::/64  netmask which is identified in the 
> ICMPv6 Prefix Information Option instead of the ::/128 netmask which 
> it is actually using?
>
> Thanks
>
> Russell
>
>
> On 01/03/2021 21:08, Gibbins, John (IM&T, Black Mountain) wrote:
>>
>> Hi Russell,
>>
>> Is this a problem?  Our systems running with the old ISC DHCP server 
>> report /128 on Ubuntu boxes for addresses handed out by DHCPv6 even 
>> though link local addresses appear as /64.
>>
>> In a sense all host addresses are /128 entries.  The important thing 
>> is that the routing table includes a route for the /64 block 
>> containing the address.  As long as that is there your system should 
>> work properly.  That should be learnt from the RA rather than DHCP.
>>
>> Regards
>>
>> johng
>>
>> *From:*Kea-users <kea-users-bounces at lists.isc.org> *On Behalf Of 
>> *russell aspinwall
>> *Sent:* Tuesday, 2 March 2021 7:32 AM
>> *To:* Torbjörn Eklöv <torbjorn.eklov at interlan.se>; 
>> kea-users at lists.isc.org; russell.aspinwall at bcs.org.uk
>> *Subject:* Re: [Kea-users] Kea 1.6 DHCP6 configuration on Raspberry 
>> Pi 3b running Ubuntu 20.04
>>
>> Hi
>>
>> Thanks for the feedback, my router is pfsense firewall and I 
>> haveconfigured the LAN side Router Advertisements as
>> Managed -RA Flags [managed. other stateful], Prefix flags [onlink, 
>> router]  but the dhcp6 client get a ::/128 address
>> I have also configured the correct RA subnet for the interface but 
>> while the clients get an IPv6 address from the pool, the subnet is 
>> still wrong.
>>
>> Thanks
>>
>> Russell
>>
>>
>>
>> On 01/03/2021 16:30, Torbjörn Eklöv wrote:
>>
>>     DHCPv6 only gives you an address, RA is the one who gives you the
>>     infrastructure.
>>
>>
>>
>>     /Torbjörn Eklöv
>>     Interlan Gefle AB
>>     mobil: 070 - 683 51 75
>>     http://test-ipv6.se
>>
>>     A home without IPv6 is just a house
>>
>>     ------------------------------------------------------------------------
>>
>>     *Från:* Kea-users <kea-users-bounces at lists.isc.org>
>>     <mailto:kea-users-bounces at lists.isc.org> för russell aspinwall
>>     <raspinwall at willows7.myzen.co.uk>
>>     <mailto:raspinwall at willows7.myzen.co.uk>
>>     *Skickat:* den 1 mars 2021 17:23
>>     *Till:* kea-users at lists.isc.org <mailto:kea-users at lists.isc.org>
>>     <kea-users at lists.isc.org> <mailto:kea-users at lists.isc.org>
>>     *Ämne:* [Kea-users] Kea 1.6 DHCP6 configuration on Raspberry Pi
>>     3b running Ubuntu 20.04
>>
>>     Hi,
>>
>>     I have successfully configured HA between two Raspberry Pi 3bs
>>     running
>>     Ubuntu server 20.04 with repository Kea 1.6 version.
>>
>>     I have configured a DHCP6 range and a pool but the client always
>>     has a
>>     ::/128 address.
>>
>>     As I have a mixture of staticly assigned  and dhcp6 clients in
>>     the same
>>     ::/64 subnet, I have specified my ::/64 subnet in the
>>
>>     {
>>                "id": 2012,
>>                "pools": [ { "pool": "NNNN:PPPP:QQQQ:T:ffff::/80" } ],
>>                "subnet": "NNNN:PPPP:QQQQ:T::/64",
>>                "interface": "eth0",
>>               "option-data" : [
>>                   {
>>                      "name": "domain-search",
>>                      "csv-format": true,
>>                      "data": "euclid.plato"
>>                   },
>>                   {
>>                      "name": "dns-servers",
>>                      "data": "NNNN:PPPP:QQQQ:T:8213:1132:6645:2222"
>>                   },
>>                   {
>>                      "name": "sntp-servers",
>>                      "data": "NNNN:PPPP:QQQQ:T:8213:1132:6645:2222"
>>                   }
>>
>>            ]
>>
>>     }
>>
>>     How I can I assign a ::/64 address which is selected from only a
>>     smaller
>>     portion of the ::/64 subnet so that the client is assigned a
>>     ::/64 address.
>>
>>     Thanks
>>
>>     Russell
>>
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