Everyone else is out of the apartment which finally gave me a chance to debug broken IPv6 connectivity. Every time I enabled IPv6 connections would start hanging for 30 seconds then suddenly come good - what looked like a classic PMTU discovery problem. However, for who knows what reason, it turns out my OpenWRT firewall config was dropping ICMPv6 neighbour-advertisement messages...

Well. Yes, that would do it.

Thus I would get about 10 seconds of connectivity while the kernel tried to do neighbour discovery then about 30 seconds of "destination unreachable". This tends to confuse the hell out of Chrome's "happy eyes" protocol and drives everyone crazy.

#ipv6 #neighbour-discovery