I can't ping ipv6 addresses from my Windows 10 machines but I can ping them directly from the router and from older versions of Windows.

I get 10/10 on test-ipv6.com from the very same Windows 10 machines.

So for me it's a Windows 10 thing.

Your mileage may vary.

I'm having the same issue from my Drayek's Ping Diagnostics:

PING through WAN1 ipv6.l.google.com || 2a00:1450:400e:806::200e

Code:

Pinging through WAN1. Pinging 2a00:1450:400e:806::200e with 64 bytes of Data: Request timed out !!! Request timed out !!! Request timed out !!! Request timed out !!! Request timed out !!! Packets: Sent = 5, Received = 0, Lost = 5 (100% loss)

Traceroute:

Code:

traceroute to 2a00:1450:400e:806::200e, 30 hops max through protocol ICMP 1 Request timed out. * 2 Request timed out. * Trace complete.

I tried a Firmware reset (v2860_3846BT_576D17.rst) with a settings restore but that has made no difference.

I did talk someone else through setting up their 2760 for IP on BT last night and there's came up and routed straight away. The main difference was that their LAN IPv6 Page was talking about RADVD, whilst my 2860 doesn't have any RADVD option that I can find !?

My search skills have obviously been weak as I have just discovered a thread on the BT user forums where other BT customers are suffering the same issues:
https://community.bt.com/t5/Connected-Devices-Other/IPv6-addresses-given-but-no-connection/td-p/1744767/page/5

tl;dr
The problem is with patchy IPv6 configuration issues on BT's network and I unfortunately live in a geographic location (Bracknell) with issues. As there is no official BT support for IPv6 yet, there is no comment on when (or if) these issues will be resolved

I've just checked my IPv6 with BT (home). Ping working from Windows 10 and router.

Code:

Pinging ipv6.l.google.com [2a00:1450:4009:80b::200e] with 32 bytes of data: Reply from 2a00:1450:4009:80b::200e: time=28ms Reply from 2a00:1450:4009:80b::200e: time=27ms Reply from 2a00:1450:4009:80b::200e: time=35ms Reply from 2a00:1450:4009:80b::200e: time=28ms

I think you are right, it could be a bad set up with BT. I had something similar at work. Fortunately that means BT business support team which are far more clued up on fixing it.

After investigating this with @desc via the BT forum it seems there are at least four users all connected to the exact same upstream BT router that are all experiencing the same problem. They all get IPv6 addresses via DHCPv6 Prefix Delegation, but traffic never gets beyond the first BT upstream router. No fix yet, but some progress as the BT Forum moderators are now going to get the issue investigated. Watch this space I guess.

Edit 15-Sep-17: For anyone finding this in the future, the problem was found to be with the BT router and is now resolved.