DHCP with 6to4

I am running 6to4 which has been working just fine. Today I decided to change the IPv4 assigned address range for DHCP. When I saved it I got an error message:

The specified IPv6 range lies outside of the current subnet (make sure the interface is configured with an IPv6 address before you enable the DHCP server).

So using the 6to4 address assigned to the LAN interface, i.e. 2002:43a6:8258:1::1, I manually set the range to be 2002:43a6:8258:1::14 to 2002:43a6:8258:1::fe. That is certainly within the IPv6 subnet assigned to the LAN interface. This did not work.

After some fiddling about I realized that the problem is in the UI. The IPv6 address range in the DHCP server page is being checked against the entered (static) IPv6 address on the LAN interface configuration page. With 6to4, no value is entered. My workaround was to statically set the IPv6 address of the LAN interface to the 6to4 address, setup DHCP to match, save the DHCP configuration, then switch the LAN interface back to 6to4.

I think that there needs to be a check in the DHCP configuration so that, if the router is doing 6to4, the range is set to match the span (number of addresses assigned) of the IPv4 DHCP server, and the subnet is picked up from the current IPv6 address in the LAN interface.

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Brian Lloyd                         3191 Western Drive
brianl AT lloyd DOT com             Cameron Park, CA 95682
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