We've had some intermittent network problems at home lately - random timeouts and stuff seemingly down just for us. Then I was trying to download some software libraries today and it failed, giving the reason that it couldn't connect to an IPv6 address. Then I found http://test-ipv6.comcast.net/ and noticed it's failing as follows:
Test with IPv6 DNS record = timeout
Test IPv6 without DNS = timeout
Test IPv6 large packet = timeout
Find IPv6 Service Provider = timeout
My router (Arris SBG10) has IPv6 DHCP enabled for both the WAN and LAN. The router thinks it has an IPv6 address from DHCP but none of the tools that report your IPv6 IP address are saying "Not Detected" for IPv6. My laptop also thinks it has an IPv6 address on the local network, but can't ping any IPv6 addresses.
I know we have IPv6 support because I've seen it work previously. Is Comcast having an issue?
if you go to the IPv6 settings for your router, is there an Auto Detect or Auto Config option?
I'm having the same issue. I get the same timeouts on the IPv6 test. Facebook and Mario Kart Tour apps don't launch on my phone, and our Google Home Mini's always time out on the first request after idling. Everything else works fine. It seems to be an IPv6 issue.
My router is the Arris TG1682G. There are no settings to configure IPv6 so it seems like I'm stuck. The only thing I haven't tried yet is factory resetting the router...
So I fixed the issue with random timeouts with IPv6 hosts with a new router. I got a Netgear C3700v2 and went to the Advanced Settings > IPv6, and changed the "IP Address Assignment" setting from "Auto Config" to "Use DHCP Server". The IPv6 tests report that I don't have IPv6, but they no longer timeout, and everything else on the network is now working normally.