I'm using an HE tunnel for ipv6, connected through a pfsense router. ipv6-test.com and test-ipv6.com both indicate ipv4 and ipv6 are workign properly. However, over the past few days, I've noticed a few websites that aren't accessible, e.g., mail.yahoo.com and speedtest.xfinity.com. tracert -4 and -6 both work, but I can only access the sites when I disable ipv6 on the client, which is windows. I've also noticed that mobiles connected to the wifi are having the same problem. Changing to a different browser doesn't make any difference either. To eliminate the router, I upgraded to the latest version. It made no difference. To eliminate the tunnel, I tested using a different pfsense router, running a development version of pfsense on another computer, which is configured to use native ipv6. The problem doesn't occur on this configuration, so it's looking like there is a routing problem with the tunnel. Any suggestions what to do with this?