[180724] in North American Network Operators' Group
RE: Android (lack of) support for DHCPv6
daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Wed Jun 10 03:02:42 2015
X-Original-To: nanog@nanog.org
Date: Wed, 10 Jun 2015 08:59:56 +0200 (CEST)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: Tony Hain <alh-ietf@tndh.net>
In-Reply-To: <10cd01d0a348$0e494500$2adbcf00$@tndh.net>
Cc: nanog@nanog.org
Errors-To: nanog-bounces@nanog.org
On Tue, 9 Jun 2015, Tony Hain wrote:
> I filed a platform bug on this back in the ICS timeframe, and it still
> persists. As I recall, there are 2 flags provided by the OS related to RA
> handling. Rather than using the one that sets a preference between the Cell
> vs. Wifi interface, at least Samsung (possibly others) have chosen to use
> the other flag that says to completely ignore the WiFi RA if an RA on the
> Cell interface has ever occurred. This means devices that have no IPv6 on
> their Cell interface will appear to work fine on WiFi.
I just re-verified (same Nexus4 using 5.1.1 on swedish mobile provider
Tele2):
I disable wifi.
I have dual stack on my mobile bearer (PDP context). Verified with 10/10
for both ipv4 and ipv6 on test-ipv4.com (no 464xlat though, this is
NAT44:ed IPv4 and native IPv6 on the mobile side).
I enable wifi.
After a few seconds the Nexus4 connects to my home wifi and starts using
it, I get 10/10 for IPv4 on test-ipv4.com and 9/10 for IPv6 because my
provider DNS resolver doesn't support native IPv6 lookups.
> I claim that there is a platform bug, because there is never a reason to
> ignore the WiFi RA. Use the other flag to set a preference if that is
> needed, but ignoring the RA just breaks things in unexpected ways. LC
> has did a hand-wave that the "ignore RA" flag is needed for battery
> life, but beyond that we appear to be stuck in a world where Clueless
> OEMs believe in breaking one network when another might exist.
Well, it's not present on my Google device anyhow.
--
Mikael Abrahamsson email: swmike@swm.pp.se
