[Dnsmasq-discuss] IPv6 - Router Advertisement

Tsachi tsachi.kimel at gmail.com
Fri Nov 15 12:10:36 GMT 2013


Thanks Simon,
I will test it and let you know.
Also what do you say regarding including "router lifetime=0" in the RA
msg in this case ?
Regards,
Tsachi

On Fri, Nov 15, 2013 at 1:27 PM, Simon Kelley <simon at thekelleys.org.uk> wrote:
> OK, I found the problem,
>
> http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=dd9d9ce54c46b0e110f71f8cb19934bd2e8ae656
>
> or
>
> dnsmasq-2.68test2 should fix it. The patch will apply to 2.67, if you'd
> rather do that.
>
>
> Thanks for the report.
>
>
> Cheers,
>
> Simon.
>
>
>
> On 14/11/13 17:38, Tsachi wrote:
>>
>> Hi,
>> I have a question regarding dnsmasq behavior regarding IPv6 RA message
>> while using the "constructor" config option.
>> Version details: Kernel 2.6.35, Dnsmasq ver 2.67
>>
>> I am working on a small Linux router device which obtains a single
>> dynamic global \64 prefix from a network (the prefix is changing every
>> time the device connects to the network).
>>
>> This prefix is published (RA) on the device LAN interface (eth0) for
>> the purpose of hosts Global address generation (using SLAAC).
>>
>> The following dnsmasq ipv6 configurations are set:
>> dhcp-range=::,constructor:eth0, ra-only,64,60
>> log-dhcp
>> dhcp-option=option6:23,[::]
>> ra-param=eth0,20
>>
>>
>> The LAN interface (eth0) starts with link local address.
>>
>> After the device connects to the network, a new ipv6 global address is
>> manually assigned to the eth0 interface ( \64 constructed from the
>> prefix that the device received).
>>
>> ip addr add 2002::21a:2bff:fe3c:4d5e/64 dev eth0
>>
>> As expected, this triggers periodic unsolicited RA messages (and RA
>> responses to RS).
>> Log shows the following RA messages - "RTR-ADVERT(eth0) 2002::"
>>
>> After some time the device disconnects from the network and then the
>> eth0 IPv6 address is removed:
>>
>> ip addr del 2002::21a:2bff:fe3c:4d5e/64 dev eth0
>>
>> The log shows the following RA messages " router advertisement on
>> 2002::, old prefix for eth0"
>>
>> But the log doesn't show – "RTR-ADVERT" messages (nor the device sends
>> any RA after, and will not response to RS requests).
>>
>> I was hoping to see an unsolicited RA massage (RTR-ADVERT) announcing
>> this prefix with preferred-time=0 and maybe also "router lifetime=0",
>> so hosts are aware of the disconnection.
>>
>> What do you think regarding unsolicited RA massage when the interface
>> global ip address is deleted?
>>
>>
>> By the way, In a different scenario, if I delete the interface ipv6
>> address and add a new one, the log shows:
>>
>> router advertisement on 2012::, old prefix for eth0
>> router advertisement on 2055::, constructed for eth0
>> RTR-ADVERT(eth0) 2055::
>> RTR-ADVERT(eth0) 2012:: old prefix
>>
>>
>> The second prefix is sent with "preferred-time=0", as expected.
>> Thanks,
>> Tsachi
>>
>> _______________________________________________
>> 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



More information about the Dnsmasq-discuss mailing list