Every few minutes (anywhere from 4 to 10 minutes) I see the following warning message in the log:
daemon.warn odhcpd[2621]: A default route is present but there is no public prefix on lan thus we announce no default route by setting ra_lifetime to 0!
I don’t know how to interpret this. And I know so little about IPv6 that I don’t know how to ask an intelligent question about this..
The LuCI Network Interfaces shows that my ISP is providing an IPv6-DP prefix. Is that the public prefix that odhcp is saying doesn’t exist? Am I supposed to set something to get this prefix used on my LAN? Do I want the public prefix used on the LAN?
At the very least, is there something I should do to prevent these messages from filling the log?
The "public prefix" mentioned in this log refers to the IPv6 prefix delegated by your ISP through DHCPv6-PD. It is not a prefix that needs to be manually created on the router.
The message means that odhcpd detected an IPv6 default route on the WAN side, but currently cannot find a usable public IPv6 prefix for the LAN side. To avoid advertising an invalid IPv6 default route to clients, it sets the RA lifetime to 0.
If you want your LAN devices to obtain global IPv6 addresses and access IPv6 Internet directly, then using the public prefix on LAN is the expected configuration.
Please go to NETWORK → IPv6, enable IPv6, select Native as the LAN mode, keep the DNS acquisition method set to Automatic, and then click Apply.
In Native mode, the router should automatically assign part of the IPv6-PD prefix received from the ISP to the LAN. There is no need to manually enter the WAN IPv6 address or the delegated prefix on the LAN interface.
Those were already set. I’ve looked in the LuCI Network Interfaces display and see that my ISP has provided an IPv6-PD starting 2601:. But the LAN is not getting it from the router.
I’ve been using the GL-MT6000 since January, but I’m not sure I’ve ever checked IPv6 on it. I am pretty sure I did not see the flood of this message before switching from v4.8.3-op24 to v4.9.0-op24. Maybe I’ll switch back to v4.8.3-op24 (or forward to 4.9.1-op25) when I have a chance. But that won’t be for a day or two. Is there anything else I should check in the mean time?
