[Dnsmasq-discuss] Using IPv6 DHCP

Sean Boran sean at boran.com
Tue Sep 25 13:38:59 BST 2012


Hi,

Ah. Its works, magic. 'Doh', as they say over the water).
So, I should use the option ra-names?

I now see logs like:
Sep 25 13:57:39 sisdns6 dnsmasq-dhcp[2282]: 14525054 DHCPSOLICIT(eth0)
00:01:00:01:00:50:10:5a:de:08
Sep 25 13:57:39 sisdns6 dnsmasq-dhcp[2282]: 14525054
DHCPADVERTISE(eth0) 2001:918:ffcb:199::16 00:01:00:01:00:50
 :10:5a:de:08
And the test client has correctly received 2001:918:ffcb:199::16.


However, if I may piggyback a question, how do I get this into DNS?

host 2001:918:ffcb:199::16 localhost
Using domain server:
Name: localhost
Address: 127.0.0.1#53
Aliases:
Host 6.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.9.9.1.0.b.c.f.f.8.1.9.0.1.0.0.2.ip6.arpa
not found: 3(NXDOMAIN)

Hmm. Looking at /var/lib/misc/dnsmasq.leases there is a star for the hostname.
So maybe the problem is ubuntu not sending a hostname.
Is there any additional option to allow dnsmasq to be more inventive
in finding out the hostname to map?
Of make dnsmask log what details it has received in the request?


Thanks,

Sean






On 25 September 2012 13:45, Simon Kelley <simon at thekelleys.org.uk> wrote:
>  Doh!
>
> I didn't read your config carefully enough. You're declaring the dhcp-range
> as "ra-stateless", which tells dnsmasq to advertise that subnet via
> router-advertisements, and set the bits which tell the clients to use DHCPv6
> for configuration, but not address allocation.
>
> Clients are expected to send DHCP information-requests for DNS servers, NTP
> servers, etc, etc, but won't get IP addresses allocated via DHCPv6. Hence
> dnsmasq is refusing to allocate and address.
>
> Remove ra-stateless from your config and it will all work.
>
>
> (On the v6-only question, if you don't supply a DHCPv4 address range, then
> dnsmasq won't reply to DHCPv4 requests.
>
> Cheers,
>
> Simon.
>
>
> On 25/09/12 10:41, Sean Boran wrote:
>>
>> Hi,
>>
>> On 25 September 2012 10:27, Simon Kelley <simon at thekelleys.org.uk> wrote:
>>>
>>> On 25/09/12 09:10, Sean Boran wrote:
>>>>
>>>>
>>>> Hi,
>>>>
>>>> I'm doing sdome DHCPv6 tests and have a few questions :-)
>>>>
>>>> First is it is possible to disable v4 respond, and only respond to v6
>>>> requests? When testing I dont want to disturb a v4 dhcp already
>>>> running.  (e.g. should I set listen-address to my IPv6 address?)
>>>
>>>
>>>
>>> If you're happy to use the very latest code, then grab 2.64test5 and add
>>> dhcp-ignore=!DHCPv6
>>>
>>> to your configuration.
>>
>>
>> I also disable "enable-ra", since ra should not be needed, when using
>> dhcp?
>>
>>
>> Sep 25 11:33:55 sisdns6 dnsmasq[9577]: started, version 2.64test5
>> cachesize 150
>> Sep 25 11:33:55 sisdns6 dnsmasq[9577]: compile time options: IPv6
>> GNU-getopt no-DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack
>> Sep 25 11:33:55 sisdns6 dnsmasq-dhcp[9577]: DHCPv6 stateless on
>> 2001:918:ffcb:199::10
>> Sep 25 11:33:55 sisdns6 dnsmasq-dhcp[9577]: SLAAC on
>> 2001:918:ffcb:199:: prefix valid 1d
>>
>>
>>>>
>>>> Secondly, I'm having issues assigning v6 addresses.
>>>>
>>>> compiled dnsmasq-2.63, config:
>>>> --
>>>> domain=mydomain.net
>>>> dhcp-range=2001:918:ffcb:199::10, 2001:918:ffcb:199::20, ra-stateless,
>>>> 24h
>
>                                                              ^^^^^^^^^^^
>
>>>> dhcp-sequential-ip
>>>> enable-ra
>>>> dhcp-option=option6:dns-server,[::]
>>>> log-dhcp
>>>> --
>>>>
>>>
>>> Does the relevant interface have an address on the 2001:918:ffcb:199::
>>> subnet, and prefix length 64?
>>
>>
>> Yes.
>>
>>   ifconfig
>> eth0      Link encap:Ethernet  HWaddr 00:50:56:83:3a:d4
>>            inet addr:10.90.199.11  Bcast:10.90.199.255  Mask:255.255.255.0
>>            inet6 addr: 2001:918:ffcb:199:fc54:9480:e886:e639/64
>> Scope:Global
>>            inet6 addr: 2001:918:ffcb:199:250:56ff:fe83:3ad4/64
>> Scope:Global
>>            inet6 addr: fe80::250:56ff:fe83:3ad4/64 Scope:Link
>>
>>
>>>
>>> Please could you try without the dhcp-sequential-ip option. That's
>>> unlikely
>>> to have been well tested for DHCPv6, and smells suspicious to me.
>>>
>>> Cheers,
>>>
>>> Simon.
>>
>>
>> Thanks done that, but no change really.
>>
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 available DHCP
>> range: 2001:918:ffcb:199::10 -- 2001:918:ffcb:199::20
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 DHCPSOLICIT(eth0)
>> 00:01:00:01:00:50:10:5a:de:08
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 requested options:
>> 24:domain-search, 39:FQDN, 23:dns-server,
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 requested options:
>> 31:sntp-server
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 tags: DHCPv6, eth0
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 sent size: 10
>> option:  1 client-id  00:01:00:01:00:50:10:5a:de:08
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 sent size: 14
>> option:  2 server-id  00:01:00:01:17:f2:f6:90:00:50:56:83:3a:d4
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 sent size: 40
>> option:  3 ia-na  IAID=1451433281 T1=0 T2=0
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 nest size: 24
>> option: 13 status  2 No addresses available
>> Sep 25 11:38:46 sisdns6 dnsmasq-dhcp[937]: 7022133 sent size: 16
>> option: 23 dns-server  2001:918:ffcb:199:fc54:9480:e886:e639
>>
>> Regards,
>>
>> Sean
>>
>



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