I have a network of computers and a wireless router here. IPv4 addresses are rfc1918 handed out by isc-dhcpd and ipv6 is provided by radvd. I've also got WPAD telling all the machines to use our squid proxy and a firewall rule that stops them using the web directly (redirect for ipv4, block for ipv6) This is mostly working well. I've got ten desktop machines (debian 6.0) and a raspberry pi and two laptops which are all quite happy to pick up both addresses. They try to use ipv6 by default and fall back to ipv4 when they need to so I think it's all set up correctly. But then I noticed that my phone, Ideos X5 running Aurora 4.0.4 rom, really doesn't like the network. If I turn on Wifi the phone starts to connect and then does a hard reboot. When it comes back up it will do the same again after a few seconds. It seems to be related to ipv6 because if I turn off radvd and let it connect it's fine. It'll even stay up if I turn radvd back on after it connected, and it will pick up an ipv6 address too. So I thought this was probably just a bug in the Aurora rom but this week a friend lent me a cheap 51cube cherry tablet, running Android 4.0.4 whatever rom the tablet came with. It does exactly the same thing. So is this an Android bug or something wrong with how my network is set up? And even if it's a bug, is there some way I can automatically have radvd wait a bit before answering or some other similar workaround so that it doesn't make my phone crash all the time?