Hiya,
this has kept me busy for days now and I still haven't found a way to resolve it:

Installed OpenWrt on an ASUS RT-N56U and configured it to work as a repeater following this description:
https://geeklabor.de/archives/198-OpenW … elayd.html

Got everything working fine, but then there is one issue that I can't cope with: Any device being connected to the LAN ports only gets a local IPv6 address. When in contrast to that I use the wireless connection everything is fine. Both laptop and cell phone receive a public IPv6 address and everything works like a charm.

Why doesn't that work for the LAN ports as well? The main router is a Fritz!Box 7490 by the way.
Thanks for any kind of help in advance

(Last edited by taxidriver on 6 Jan 2018, 11:41)

And when you set IP on the lan device as static, everything works, right? I recall I had this problem with relayd too, but it was the only solution I came up with.

No - actually I had not checked that before receiving your reply, but meanwhile I've given it a try and that way it doesn't work eitherl. Additionally I have even given the device on the repeater's LAN socket a fixed IPv6 address (guessed from the prefix delegation)...still IPv6 did not work.

You might want to try v6brouter, rather than relayd. Of course the real answer is to get your ISP to support prefix-delegation (or switch to one that does).

https://github.com/cvmiller/v6brouter

Yes, I might go a different path and try v6brouter once in a while, but before that I'd like to understand why my configuration of OpenWrt isn't doing the job.

I have recently set up a new interface WWAN6 and when I list my interfaces now that WWAN6 has an IPv6 line plus a line IPv6-PD, so I guess that my ISP does support prefix delegation. Connecting to the WLAN on the repeater lets me use IPv6 to the full extent but it's not working with the LAN ports.
That's the issue that keeps me busy, understand?

(Last edited by taxidriver on 10 Jan 2018, 21:35)

Having PD support is great. Not sure what is wrong with your config that your LAN connected devices don't work.

You _may_ want to back up your config, then default it, and see if the default works. I have had good success with OpenWrt and IPv6 right out of the box (read: with the defaults).

Ok, but you're not using your OpenWrt device in repeater mode, I think. That's why I can't go back to the default values, you see?

My guess is that the main router (FritzBox 7490) and its dhcp service might cause this issue. At least I read about this problem on some other forum boards. Unfortunately no one ever posted a solution.

Maybe I'll replace the main router with a device running OpenWrt as well, hoping that this will make a difference.

Ah, your OpenWrt router is down stream of another router (that is connected to the ISP).

You will need 2 things for this to work:
1) You ISP needs to give you more than a /64 prefix delegation (preferably something like a /56), so you can sub-divide the block
2) You router connected to the ISP needs to be able to do prefix delegation to downstream routers (OpenWrt can do this).

Thanks,

and can you be a little more specific on how this can be done in detail?
I discovered that the main router (Fritzbox 7490) is getting a /56 prefix delegation.
When I set the OpenWrt GUI of my new device WWAN6 to
"Request IPv6-prefix of length" : Automatic
I can see this: IPv6-PD: XXXX:XXXX:112d:50fc::/62
What would I have to do to subdivide the block as you say?
Does it make sense to have identical IPv6 ULA-Prefix for both the ISP router and the OpenWrt router?

I believe the Fritzbox will not do DHCP-PD downstream. When running an OpenWrt router, and another OpenWrt router downstream, it will automagically happen (odhcpd supports downstream DHCPv6-PD). So there really is nothing to configure, as long as the router connected to the ISP has more than a /64.

As to the ULA, I would suggest configuring the /48 at the ISP connected router, and let the downstream routers get addresses via DHCPv6-PD.

DO NOT put in the same ULA/48 on both routers. Routers work by routing between different networks. If you make them the same the routers will not route the ULA packets.