[Dnsmasq-discuss] Difference between SLAAC and RA-ONLY mode

[Shixiong Shang]

Tried and verified it! Working pretty well now! Thanks, Simon!

Shixiong



On Dec 19, 2013, at 10:48 AM, Simon Kelley <simon at thekelleys.org.uk> wrote:

> On 18/12/13 15:21, Shixiong Shang wrote:
>> Hi, Simon:
>> 
>> This is very helpful! Thanks a lot for your confirmation!
>> 
>> A quick question, is there any way we can set M-bit to 1 and set
>> A-bit to 0? In other words, I am trying to force VM to use DHCPv6
>> only, but not SLAAC?
> 
> Yes, configure the dhcp-range _only_ for DHCPv6 ie
> 
> 
> dhcp-range=<prefix>::1,<prefix>::200
> 
> and set the --enable-ra flag
> 
> That will do RA just to support the DHCPv6, ie MO bits set, A bit clear.
> 
> 
> Cheers,
> 
> Simon.
> 
>> 
>> Thanks again!
>> 
>> Shixiong
>> 
>> 
>> 
>> 
>> 
>> 
>>> On Dec 17, 2013, at 1:08 PM, Simon Kelley<simon at thekelleys.org.uk>
>>> wrote:
>>> 
>>>> On 17/12/13 17:34, Shixiong Shang wrote: Hi, Simon:
>>>> 
>>>> Thanks a lot for your quick clarification! Just want to make sure
>>>> I clearly understand what you mean….if the dhcp-range contains a
>>>> range of IPv6 address, then slaac should enable dhcpv6 + ra; if
>>>> the dhcp-range contains the single IPv6 address, then slack will
>>>> only do ra, but not dhcpv6…..Same as ra-only. In other words,
>>>> how slaac/ra-only set MOAL bits depends on dhcp-range…..Is my 
>>>> understanding correct?
>>> 
>>> That's correct.
>>> 
>>> 
>>> Simon.
>>> 
>>>> 
>>>> Shixiong
>>>> 
>>>> 
>>>> 
>>>> On Dec 17, 2013, at 11:55 AM, Simon
>>>> Kelley<simon at thekelleys.org.uk> wrote:
>>>> 
>>>>>> On 17/12/13 12:29, Shixiong Shang wrote: Hi, guys:
>>>>>> 
>>>>>> I tried both “slaac” mode and “ra-only” modes with dnsmasq 
>>>>>> version 2.66. One thing I noticed was, both modes set the
>>>>>> same bit value in the RA:
>>>>>> 
>>>>>> M-bit = 0, O-bit = 0, A-bit = 1, L-bit = 1.
>>>>>> 
>>>>>> I am wondering what’s the difference between these two modes 
>>>>>> then? Would you please shed some light on it?
>>>>> 
>>>>> There's no difference: "slaac" and "ra-only" have exactly the
>>>>> same effect. Reading back the manpage, the description is very
>>>>> confusing and should be re-written.
>>>>> 
>>>>> The reason for having two different keywords is that they can
>>>>> be used with and without DHCP
>>>>> 
>>>>> dhcp-range = 1234::1, 1234::100, slaac
>>>>> 
>>>>> will do RA with MOAL bits all set, and provide DHCPv6
>>>>> 
>>>>> dhcp-range = 1234::1, slaac
>>>>> 
>>>>> will do RA with only AL bits set, and not DHCP. It's maybe
>>>>> clearer to be able to be able to write.
>>>>> 
>>>>> dhcp-range = 1234::1, ra-only
>>>>> 
>>>>> in this case.
>>>>> 
>>>>> Cheers,
>>>>> 
>>>>> Simon.
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>>> 
>>>>>> Thanks!
>>>>>> 
>>>>>> Shixiong _______________________________________________ 
>>>>>> Dnsmasq-discuss mailing list 
>>>>>> Dnsmasq-discuss at lists.thekelleys.org.uk 
>>>>>> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>>>>> 
>>>>> 
>>>>> 
>>>>>> 
> _______________________________________________ Dnsmasq-discuss
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