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rchandra
Stargate Universe fan
Premium
join:2000-11-09
14225-2105

1 recommendation

IPv6-only "main" SSID at FOSDEM 2014 trips up Android

At FOSDEM this year, the "main" SSID offered only RAs (not sure if any DHCPv6) and no DHCP. Any access to the IPv4 Internet was provided by means of DNS64 and NAT64. If you somehow needed native IPv4 connectivity, you could associate to an AP with the SSID of "Fosdem-dualstack" and apparently the vast majority of Android devices needed to do that. Others kludged it by going into the advanced properties of their WiFi connection and providing bogus static information (such as an address of 0.0.0.0). More on this from one of the network's admins here, with one of the included links, to Android's bug 32630 which has been open since 3-Jun-2012!

I couldn't believe my eyes. I had to try that myself. I logged onto my router (which is separate from my AP), stopped dhcpd(8), and toggled WiFi off then on on my Nexus 7. Sure enough, when it failed to get any DHCPOFFERs after the timeout period, the sucker reset the AP association, and just tried over and over again, refusing to show the WiFi as connected. As I don't have DNS64 nor NAT64 set up, I expected that sort of failure, essentially cutting myself off from the v4 Internet, but jeesh!

whiskey tango foxtrot?
--
English is a difficult enough language to interpret correctly when its rules are followed, let alone when a writer chooses not to follow those rules.

Jeopardy! replies and randomcaps REALLY suck!



tubbynet
reminds me of the danse russe
Premium,MVM
join:2008-01-16
Chandler, AZ
kudos:1

said by rchandra:

whiskey tango foxtrot?

while not entirely the same -- there are settings in most modern linux distributions that will cause the network connection to fail if either ipv4 or ipv6 does not receive a configuration. this can be disabled on a per-interface basis -- but i'm guessing this isn't exposed via the android network stack api.

q.
--
"...if I in my north room dance naked, grotesquely before my mirror waving my shirt round my head and singing softly to myself..."

cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8

Android doesn't expose anything at all about IPv6. If you don't install a terminal app, you'll never even it's there.

All you get is the result of answering "Y" to "IPv6 Support?" in the kernel. And the most annoying bit... absolutely no way to shut the shit off without rooting the device.



tubbynet
reminds me of the danse russe
Premium,MVM
join:2008-01-16
Chandler, AZ
kudos:1

said by cramer:

Android doesn't expose anything at all about IPv6.

good to know.
i've never used an android device. ios hides the same things from you. i've never used it on an ipv6 only network, however.

q.
--
"...if I in my north room dance naked, grotesquely before my mirror waving my shirt round my head and singing softly to myself..."


Cabal
Premium
join:2007-01-21
Reviews:
·Suddenlink

1 recommendation

reply to cramer

said by cramer:

Android doesn't expose anything at all about IPv6. If you don't install a terminal app, you'll never even it's there.

As of 4.4, you can go into About phone -> Status and see all IP addresses, including link-local.

You're correct it's not configurable, though.
--
If you can't open it, you don't own it.

quesix

join:2005-12-19
Cary, IL

1 edit
reply to rchandra

there is also an App for that "IPv6 and More" that will show interface info. I cannot guarantee safety of this app. The app also generates random private IPv6 address blocks, and has links to other info. I've used with old Droid X and my current 4.1.2 android phone which uses Ipv6 4G network locally (with NAT64/DNS64 i'm assuming based on reports) on cellular. I'm guessing bug is only on IPv6-only wifi. (works fine on dualstack wifi).


cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:8
reply to Cabal

Noted. (dig deep into locations no one even thinks about, instead of putting where you actually configure the network. but then, marking APs as "hotspots" isnt' very logical either.)



connections

@pppoe.ca
reply to cramer

said by cramer:

Android doesn't expose anything at all about IPv6. If you don't install a terminal app, you'll never even it's there.

That in itself means nothing. The same could be said about iOS.


connections

@pppoe.ca
reply to rchandra

said by rchandra:

At FOSDEM this year, the "main" SSID offered only RAs (not sure if any DHCPv6) and no DHCP. Any access to the IPv4 Internet was provided by means of DNS64 and NAT64. If you somehow needed native IPv4 connectivity, you could associate to an AP with the SSID of "Fosdem-dualstack" and apparently the vast majority of Android devices needed to do that. Others kludged it by going into the advanced properties of their WiFi connection and providing bogus static information (such as an address of 0.0.0.0). More on this from one of the network's admins here, with one of the included links, to Android's bug 32630 which has been open since 3-Jun-2012!

I couldn't believe my eyes. I had to try that myself. I logged onto my router (which is separate from my AP), stopped dhcpd(8), and toggled WiFi off then on on my Nexus 7. Sure enough, when it failed to get any DHCPOFFERs after the timeout period, the sucker reset the AP association, and just tried over and over again, refusing to show the WiFi as connected. As I don't have DNS64 nor NAT64 set up, I expected that sort of failure, essentially cutting myself off from the v4 Internet, but jeesh!

whiskey tango foxtrot?

This has been a known issue for quite some time now and it isn't a matter of the vast majority; it's all devices running Android to date. It is irrelevant if you have NAT64 setup or not; Android is broken in v6 only environments. Windows / OS X / iOS / Windows Phone 8 and Linux based OS's work fine.