[Dnsmasq-discuss] Cannot assign IPv6 address for /96 subnet

Simon Kelley simon at thekelleys.org.uk
Fri Mar 15 14:25:20 GMT 2013


On 14/03/13 01:57, Sheng Yang wrote:
> Interesting, the newer version seems no longer allow such line in the
> configuration file?
>
> dhcp-range=fc00:3:1602::7473,96,static
>
> dnsmasq keeps complaining about bad dhcp-range, for version 2.66test21.
>
> Use the 2.62 is fine(though different cidr not working for dhcp-host).


Ah! This might explain everything! That dhcp-range is wrong, and 2.66 is 
correct to reject it. The parsing code has been tightened up since 2.62

the configuration you need is

dhcp-range=fc00:3:1602::7473,static,96


If I was to do dnsmasq again from scratch, I'd re-design the 
configuration syntax to avoid this sort of ambiguity.



Simon.



>
> --Sheng
>
> On Fri, Mar 8, 2013 at 9:53 AM, Simon Kelley <simon at thekelleys.org.uk> wrote:
>> On 07/03/13 22:38, Sheng Yang wrote:
>>>
>>> Hi Simon,
>>>
>>> Any chance you can reproduce it?
>>>
>>> If dhcp-range can accept a prefix rather than 64 then hand it out, I
>>> think dhcp-host should also able to do so...
>>
>>
>> I just tested 2.66test21, and it worked fine for me. I didn't test earlier
>> code.
>>
>> I've re-written huge chunks of relevant code for test21, without actually
>> looking at this problem. So either I've not got the same conditions as you
>> and the bug is still there, or I've done a better job this time round as
>> fixed the bug without doing so explicitly.
>>
>>
>> Please could you give 2.66test21 a go with you config, and see how you get
>> on?
>>
>>
>>
>> Cheers,
>>
>> Simon.
>>
>>
>>>
>>> --Sheng
>>>
>>> On Wed, Feb 20, 2013 at 2:58 AM, Simon Kelley<simon at thekelleys.org.uk>
>>> wrote:
>>>>
>>>> On 20/02/13 02:16, Sheng Yang wrote:
>>>>>
>>>>> Hi Simon,
>>>>>
>>>>> Did you use dhcphost option? dhcp-range works for me(if I specify a
>>>>> range), but not with dhcp-host option(when I specify dhcp-range as
>>>>> static).
>>>>
>>>>
>>>> Ah, no, I didn't. I should have read back through the thread. I'll check
>>>> again, but it rather looks like this is non possible, by design,  (or
>>>> miss-design)
>>>>
>>>> Simon.
>>>>
>>>>>
>>>>> --Sheng
>>>>>
>>>>> On Tue, Feb 19, 2013 at 1:06 PM, Simon Kelley<simon at thekelleys.org.uk>
>>>>> wrote:
>>>>>>
>>>>>> So, I did some testing. I configured an server interface with
>>>>>> prefix-length
>>>>>> 96, and configured dnsmasq with a dhcp-range and 96 prefix.
>>>>>>
>>>>>> Using dhclient, I got a lease successfully.
>>>>>>
>>>>>> The only problem is that dhclient configured the client's interface
>>>>>> with
>>>>>> prefix-length 64.
>>>>>>
>>>>>> I moment's thought shows that this is expected: there is nowhere in the
>>>>>> DHCPv6 messages for the prefix-length information to be passed to the
>>>>>> client. There _is_ a prefix-length field in router-advertisements. but
>>>>>> AFAIK, there's no way for the DHCPv6 client to use that information.
>>>>>>
>>>>>> Of course if you're using RA for address-allocation, using SLAAC, the
>>>>>> prefix
>>>>>> length has to be 64 anyway.
>>>>>>
>>>>>> If anyone knows better, or can explain how the standard(s) are supposed
>>>>>> to
>>>>>> work, please enlighten me.
>>>>>>
>>>>>> Simon.
>>>>>
>>>>>
>>>>
>>>
>>
>




More information about the Dnsmasq-discuss mailing list