IPv6 Default Gateway not sicking
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I am on Comcast as well, and I would recommend that you check the somewhat mysteriously named "IPv4 connectivity via parent" box; without that, IPv6 connectivity will not recover from temporary loss of upstream connectivity (e.g., unplug modem without rebooting it).
Enabling this breaks my IPv6 connection.
Even after a subsequent reboot? Bizarre, works just fine for me…
Seems to work just fine for me. Are you sure you're not accidentally blocking things? That would seem to be consistent with your symptoms.
Do you have "block bogon networks" enabled in your WAN and/or LAN interface settings by any chance? That apparently has the unfortunate side effect of blocking some ICMP6 traffic that is required for IPv6 to work properly.
Nope, I have that off on all interfaces.
Any other rule that might lead to router advertisement packets being blocked? Have you looked over /tmp/rules.debug?
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I am on Comcast as well, and I would recommend that you check the somewhat mysteriously named "IPv4 connectivity via parent" box; without that, IPv6 connectivity will not recover from temporary loss of upstream connectivity (e.g., unplug modem without rebooting it).
Enabling this breaks my IPv6 connection.
Enabling that broke it for me, too. Also, on Comcast.
- I had received IPv6 addressing initially (built a fresh 2.1-RELEASE system).
- In the middle of the night, Comcast was out for 30 minutes.
- pfs still had IPv6 addressing, but I was not able to go anywhere via IPv6 (IPv4 still worked).
- I rebooted pfs, but it would not reacquire IPv6 addressing.
- I did multiple reboots of the cable modem and pfs, but still no IPv6.
- I then unchecked "Request a IPv6 prefix/information through the IPv4 connectivity link", rebooted and then I got IPv6 back.
I'd really like a better understanding about what that option does. It may not be working as expected.
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I know this is an old thread – but I had a similar problem. I am using DHCPv6; Windows 7 would obtain an address from DHCPv6 and the default route from the router. The default route would be there (as seen via "route print") for 30 minutes. Then it would disappear.
I found that the default Windows Firewall allows ICMPv6 ONLY from fe80::/64. Normally, this is fine, however, in our infinite wisdom, we set the router's link-local address to be fe80:42::1 (which isnt part of the fe80::/64 subnet). If we let it pick its own link-local, (the default) it would have been OK.
Thus, the initial default gateway appeared because Windows requested it via Router Solicitation. But it was unable to hear the periodic Router Advertisement messages after that in order to keep that default route alive. It timed out after 30 minutes and disappeared.
We've since changed our router's link-local address to be fe80::42:1 (which IS part of fe80::/64).