[184272] in North American Network Operators' Group
Re: IPv6 and Android auto conf
daemon@ATHENA.MIT.EDU (Hugo Slabbert)
Thu Oct 1 11:56:37 2015
X-Original-To: nanog@nanog.org
Date: Thu, 1 Oct 2015 08:56:34 -0700
From: Hugo Slabbert <hugo@slabnet.com>
To: Anurag Bhatia <me@anuragbhatia.com>
In-Reply-To: <CAJ0+aXZ+AX7Gea4chOZ2kURPpVSdmW6=Qw33iBzZyYtX1idXsg@mail.gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
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On Mon 2015-Sep-28 21:15:02 +0530, Anurag Bhatia <me@anuragbhatia.com> wrot=
e:
>Hi Hugo
>
>
>(My reply in line)
>
>On Mon, Sep 28, 2015 at 8:50 PM, Hugo Slabbert <hugo@slabnet.com> wrote:
>
>>
>> On Mon 2015-Sep-28 17:33:46 +0530, Anurag Bhatia <me@anuragbhatia.com>
>> wrote:
>>
>> Hello everyone
>>>
>>>
>>>
>>>
>>> I recently got IPv6 working at home LAN. My Android device (Google Nexus
>>> 5)
>>> is connected via wifi to LAN and LAN's core router is Map2N
>>> <http://routerboard.com/RBmAP2n>. I have a /64 on the LAN with
>>> "advertise"
>>> enabled to make ND to work and have autoconfig working on all devices.
>>> There are bunch of other layer 2 devices in LAN but all just acting as
>>> layer 2 transparently and core L3 remains on Map2N.
>>>
>>>
>>> All works well for most part but only trouble I am getting is on Nexus 5
>>> where after around 24hrs IPv6 stops working.
>>>
>>
>> How, specifically, does it "stop working" on the Nexus 5?
>> - temp addresses expired and does not generate new, valid, slaac address=
es?
>> - RA entry ages out and doesn't get refreshed?
>> - cannot reach v6 gateway (ND fails somehow)?
>
>The last one - everything appears normal (with 4 IPv6 addresses on the
>device) but I cannot point any neighbor in same VLAN. Nor I can ping from
>them.
>
That sounds either like NDP is busted on the phone or the AP is eating the=
=20
Android device's ND traffic.
When this happens, does the Android device show up in the ND cache of the=
=20
other devices on the network that you are trying to reach/ping?
Does it show up in the ND cache of the segment's router?
If the Android device isn't showing up in other hosts ND caches when you=20
try to ping them, can you do a pcap on one of those hosts when you try to=
=20
initiate pings from the Android device to confirm if NS packets are being=
=20
received?
Have you tried doing captures on the Android device directly [1][2][3] to=
=20
see if it still receives RAs when this happens?
The symptoms seem to possibly line up with Android issue #32662[4]. =20
Possible you're being hit by that?
>
>The visible impact I see of it is slightly slow behavior of IPv6 enabled
>apps/websites which take a few seconds, timeout and fallback to IPv4.
>
>
>
>
>Thanks.
>
>>
>>
>> Only unusual thing I notice at that time is that phone 4 IPv6 as opposed
>>> to 2 (autoconf and temporary randomised address). Seems like some kind =
of
>>> issue in way NDP works either on Microtik or phone. The fix I am doing =
=66rom
>>> few days is to restart wifi and phone interface gets fresh (two) IPv6
>>> addresses and all works well
>>> again.
>>>
>>>
>>>
>>> Anyone facing similar issue? (Note: No issues on OS X or iOS which are =
in
>>> same LAN)
>>>
>>>
>>> I can try DHCPv6 but I guess most of devices do not support it yet. (I =
see
>>> support for that in routerboard though).
>>>
>>>
>> Unless something's changed, DHCPv6 IA_NA isn't an option for getting an
>> IPv6 address assigned to an Android device[1][2]
>>
>>
>>
>>>
>>>
>>>
>>> Thanks.
>>>
>>>
>>> --
>>>
>>>
>>> Anurag Bhatia
>>> anuragbhatia.com
>>>
>>>
>>> PGP Key Fingerprint: 3115 677D 2E94 B696 651B 870C C06D D524 245E 58E2
>>>
>>
>>
>> --
>> Hugo
>>
>> hugo@slabnet.com: email, xmpp/jabber
>> PGP fingerprint (B178313E):
>> CF18 15FA 9FE4 0CD1 2319
>> 1D77 9AB1 0FFD B178 313E
>>
>> [1] https://code.google.com/p/android/issues/detail?id=3D32621
>> [2] http://mailman.nanog.org/pipermail/nanog/2015-June/075915.html
>>
>
>
>
>--=20
>
>
>Anurag Bhatia
>anuragbhatia.com
>
>
>PGP Key Fingerprint: 3115 677D 2E94 B696 651B 870C C06D D524 245E 58E2
--=20
Hugo
hugo@slabnet.com: email, xmpp/jabber
PGP fingerprint (B178313E):
CF18 15FA 9FE4 0CD1 2319
1D77 9AB1 0FFD B178 313E
(also on textsecure & redphone)
[1] https://sites.google.com/site/androidarts/packet-sniffer (needs root)
[2] https://www.kismetwireless.net/android-pcap/ (some limitations, but=20
shouldn't need root)
[3] https://play.google.com/store/apps/details?id=3Dlv.n3o.shark (needs roo=
t)
[4] https://code.google.com/p/android/issues/detail?id=3D32662
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