[Dnsmasq-discuss] dnsmasq with dhcpv6 and dhcp-host option

[drewski theman]

Sheng Yang <sheng at yasker.org> wrote:

>On Mon, Jan 14, 2013 at 1:13 PM, Simon Kelley <simon at thekelleys.org.uk> wrote:
>> On 14/01/13 18:48, Sheng Yang wrote:
>>
>>> Another question: Could it possible to use dhcp-host with ipv6 and id:*?
>>>
>>> like this:
>>>
>>> dhcp-host=06:6f:aa:00:00:2d,id:\*,[fc00:1234:5678:1234::144],fred,infinte
>>>
>>> I found seems it doesn't work, but I found these lines in dnsmasq.conf:
>>>
>>> <quote>
>>>
>>> A single dhcp-host may contain an IPv4 address or an IPv6 address, or
>>> both. IPv6 addresses must be bracketed by square brackets thus:
>>> --dhcp-host=laptop,[1234::56] Note that in IPv6 DHCP, the hardware
>>> address is not normally available, so a client must be identified by
>>> client-id (called client DUID in IPv6-land) or hostname.
>>>
>>> The special option id:* means "ignore any client-id and use MAC
>>> addresses only." This is useful when a client presents a client-id
>>> sometimes but not others.
>>> </quote>
>>>
>>> Does this means dnsmasq is able to extract MAC from DUID, then
>>> identify the client?
>>
>>
>> Sadly, no. The DUID can't be reliably used to find the MAC. (A client with
>> more than one network interface will use the same DUID on all interfaces,
>> and it won't change if the network card is swapped-out, for instance)
>>
>> The standards people have decided that having access to the MAC address
>> would be a good idea, after all, so a new DHCPv6 is being defined. When
>> that's done, dnsmasq will support it, but at the moment it's not possible,
>> sorry.
>
>Simon, thank you for clarifying!
>
>I think let dhcp client generate DUID-LL should be a good idea in this
>case, sadly most of them would generate DUID-LLT by default...
>
>--Sheng
>>
>>
>>
>> Cheers,
>>
>> Simon.
>>
>>
>>
>
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