Android and DHCPv6 again

Wed Oct 7 01:29:14 UTC 2015

Hello,
  This is a question a should test myself but anyhow I would like to
hear your comments.
  What happen (on the client side/Android maybe)  if I advertise the DNS
information in the RA and I also enable the O bit?

Thanks,

Alejandro,

El 10/6/2015 a las 8:39 PM, Bruce Horth escribió:
> Your device may be getting an address, but without a recursive DNS server
> it may be useless.
>
> If you're going to do SLAAC you'll also need to supply your client with a
> recursive DNS server. Android prefers RFC 6106. As you mentioned, Google
> has decided not to support DHCPv6 in Android. Unfortunately some router
> manufacturers are only now getting around to implementing RFC 6106.
>
>
>
>
> BH
>
> On Sat, Oct 3, 2015 at 9:52 PM, Baldur Norddahl <baldur.norddahl at gmail.com>
> wrote:
>
>> Hi
>>
>> I noticed that my Nexus 9 tablet did not have any IPv6 although everything
>> else in my house is IPv6 enabled. Then I noticed that my Samsung S6 was
>> also without IPv6. Hmm.
>>
>> A little work with tcpdump and I got this:
>>
>> 03:27:15.978826 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 120)
>> fe80::222:7ff:fe49:ffad > ip6-allnodes: [icmp6 sum ok] ICMP6, router
>> advertisement, length 120
>> hop limit 0, Flags [*managed*, other stateful], pref medium, router
>> lifetime 1800s, reachable time 0s, retrans time 0s
>>  source link-address option (1), length 8 (1): 00:22:07:49:ff:ad
>>  mtu option (5), length 8 (1):  1500
>>  prefix info option (3), length 32 (4): 2a00:7660:5c6::/64, Flags [onlink,
>> *auto*], valid time 7040s, pref. time 1800s
>>  unknown option (24), length 16 (2):
>>  0x0000:  3000 0000 1b80 2a00 7660 05c6 0000
>>
>> So my CPE is actually doing DHCPv6 and some nice people at Google decided
>> that it will be better for me to be without IPv6 in that case :-(.
>>
>> But it also has the auto flag, so Android should be able to do SLAAC yes?
>>
>> My Macbook Pro currently has the following set of addresses:
>>
>> en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>> ether 3c:15:c2:ba:76:d4
>> inet6 fe80::3e15:c2ff:feba:76d4%en0 prefixlen 64 scopeid 0x4
>> inet 192.168.1.214 netmask 0xffffff00 broadcast 192.168.1.255
>> inet6 2a00:7660:5c6::3e15:c2ff:feba:76d4 prefixlen 64 autoconf
>> inet6 2a00:7660:5c6::b5a5:5839:ca0f:267e prefixlen 64 autoconf temporary
>> inet6 2a00:7660:5c6::899 prefixlen 64 dynamic
>> nd6 options=1<PERFORMNUD>
>> media: autoselect
>> status: active
>>
>> To me it seems that the Macbook has one SLAAC address, one privacy
>> extension address and one DHCPv6 managed address.
>>
>> In fact the CPE manufacturer is a little clever here. They gave me an easy
>> address that I can use to access my computer ("899") while still allowing
>> SLAAC and privacy extensions. If I want to open ports in my firewall I
>> could do that to the "899" address.
>>
>> But why is my Android devices without IPv6 in this setup?
>>
>> Regards,
>>
>> Baldur
>>