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

Simon Kelley simon at thekelleys.org.uk
Thu Dec 19 10:31:47 GMT 2013


On 19/12/13 04:02, Shixiong Shang wrote:
> I just found a workaround….If I replaced “slaac” mode with “static” mode, then it just worked fine…But I don’t understand why it worked. :(
>
>

What version of dnsmasq are you using? That command line doesn't 
generate an error with the latest code.


Cheers,

Simon.

>
> On Dec 18, 2013, at 1:15 PM, Shixiong Shang<sparkofwisdom.cloud at gmail.com>  wrote:
>
>> Hi, Simon:
>>
>> I put the range inside —dhcp-range filed as shown below to enable DHCPv6 mode. When I issued the command, the dnsmasq didn’t return any error. However, it failed to launch and the syslog threw errors. I am wondering which the “bad dhcp-range” refer to?
>>
>> sudo dnsmasq --no-hosts --no-resolv --strict-order --bind-interfaces --except-interface=lo --leasefile-ro --enable-ra --port=547 --dhcp-range=set:tag1,2001:db8:2::2,2001:db8:2:0:ffff:ffff:ffff:fffe,slaac --dhcp-hostsfile=/var/lib/app/dhcp/b3051625-e7de-4500-99d9-e9e80f5a8349/ipv6host --dhcp-option=tag:tag1,option6:dns-server,[2001:4860:4860::8888] --pid-file=/var/lib/app/dhcp/b3051625-e7de-4500-99d9-e9e80f5a8349/ipv6pid
>>
>> Dec 18 10:10:14 net-network2 dnsmasq[19722]: bad command line options: bad dhcp-range
>> Dec 18 10:10:14 net-network2 dnsmasq[19722]: FAILED to start up
>>
>> Thanks!
>>
>> 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
>>>>> mailing list Dnsmasq-discuss at lists.thekelleys.org.uk
>>>>> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>>>>
>>>>
>>>
>>
>
>




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