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New Router, New IPv6 Range, No IPv6 service

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New Router, New IPv6 Range, No IPv6 service

Comcast delivered a new Cisco DPC3941B today. It worked OK for IPv4. I had to poke the interface and reboot it a few times in order to get IPv6 addresses to assign to the LAN. There was something screwed up with the IPv6 DNS information to start with. Then I disabled DHCPv6 because autoconfiguration has always worked well for me. So now I have addresses but they do not work. IPv6 packets appear to vanish into thin air after the router. The router's diagnostics show it can ping IPv6 addresses. But for some reason it isn't routing them. I saw a similar message here on the forum but his problem had been solved by a full router reset? I don't see how that would help me, as this router is brand new out of the box and has been reset with fresh configuration loaded just this morning. Help and advice please! Thanks.
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Re: New Router, New IPv6 Range, No IPv6 service

I was told by support that you need to have dhcpv6 enabled on the modem and have at least one device directly connected to the modem make a dhcp request for an ipv6 address to get the ipv6 routing to work.  As for the built in diagnostics, my experience has been it uses the WAN ipv6 address, so it doesn't help any in troubleshooting problems with the LAN addresses on the modem.

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Occasional Visitor

Re: New Router, New IPv6 Range, No IPv6 service

I was told by support that you need to have dhcpv6 enabled on the modem and have at least one device directly connected to the modem make a dhcp request for an ipv6 address to get the ipv6 routing to work.  As for the built in diagnostics, my experience has been it uses the WAN ipv6 address, so it doesn't help any in troubleshooting problems with the LAN addresses on the modem.

Occasional Visitor

Re: New Router, New IPv6 Range, No IPv6 service

That must have been it. At some point IPv6 started working for me so I guess that a device must have done DHCPv6.
Occasional Visitor

Re: New Router, New IPv6 Range, No IPv6 service

No that wasn't it. IPv6 randomly works, and then it doesn't. No apparent reasons for working or not working. I did notice that the information in the router's Connected Devices for one of the not-working machines has only one correct IPv6 address. Its list does not even contain the IPv6 address that DHCPv6 assigned to it. All of the other IPv6 addresses that the router THINKS belong to the it, aren't.
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