Comcast recently lit up IPv6 native dual stack in the Boston area.

The http://test-ipv6.com/ web site complains about DNS problems unless dnssec is disabled; if it is, I get various timeouts.

Test with IPv4 DNS record		ok (4.196s)
Test with IPv6 DNS record		ok (0.115s) using ipv6
Test with Dual Stack DNS record		timeout (11.882s)
Test for Dual Stack DNS and large packet		timeout (11.817s)
Test IPv4 without DNS		ok (0.214s) using ipv4
Test IPv6 without DNS		ok (0.204s) using ipv6
Test IPv6 large packet		ok (0.120s) using ipv6
Test if your ISP's DNS server uses IPv6		slow (8.752s)
Find IPv4 Service Provider		timeout (11.968s)
Find IPv6 Service Provider		ok (0.126s) using ipv6 ASN 7922
Test for buggy DNS		undefined (5.003s)

DNS server addresses look reasonable for Comcast.

DNS 1: 75.75.75.75

DNS 2: 75.75.76.76

DNS 1: 2001:558:feed::1

DNS 2: 2001:558:feed::2

Today, the problem seems consistent with turning dnssec on and off on the router. If enabled, I have problems; if disabled, I get a clean bill of health out of test-ipv6.com.

- Jim