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

Shixiong Shang sparkofwisdom.cloud at gmail.com
Thu Dec 19 04:02:09 GMT 2013


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. :(



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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