IPv6 connections timeout

Can anybody at least here help me troubleshoot? Need help with this ---> http://ubuntuforums.org/showthread.php?t=2258021

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I'm having issues with IPv6 connections. Only with those. They timeout roughly every 10 minutes (due to address renewal i suppose).

Happens with every debian based flavour of linux i tried in a year or so, x86 and x64, across different PCs, wired and wireless.

Currently using kernel 3.13.0-37-generic x86_64; previously 3.2.0-60. Sometimes when i try to immediately restart the download i get "no route to host." because my IPv6 addresses seem to be momentarily gone.

I'm running dual stack IPv4 - IPv6 (PPPoE), this is how my Netgear DGND3700v2 router (firmware version V1.1.00.22_1.00.22) is configured: http://i.imgur.com/YgxAyQb.png

The network profile in question (network-manager version 0.9.8.8) is set to ignore IPv6 but i'm getting global IPv6 addresses anyway. Changing to auto does not make any difference. This is confusing but i guess it's just the kernel doing its job.

Firewall rules or lack thereof don't make any difference but they basically are:

iptables -P INPUT DROP
ip6tables -P INPUT DROP
iptables -P FORWARD DROP
ip6tables -P FORWARD DROP
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
ip6tables -A INPUT -i lo -j ACCEPT
ip6tables -A OUTPUT -o lo -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
ip6tables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
ip6tables -I INPUT  -p icmpv6 -j ACCEPT

Tried using DHCP instead of autoconf for the LAN, now i get no timeouts on windows but no ipv6 connectivity on linux (even though i appear to have a global address but i'm getting "network unreachable" errors anyway).