Need Help: Setting Up Separate OpenWRT IPv6 Network in Large House

Hi everyone,

I'm having some trouble setting up a separate private network in my large 4-floor house and could really use some advice.

Current Setup:

  • WiFi Network: TotoLink X8 mesh network
  • Node Connections: Due to the house's size, nodes are connected via Ethernet through a switch (mesh wireless doesn't reach)
  • Network Structure:
    • ISP Modem/Router/Voice (FTTH) Huawei (HG8245Q)
    • TotoLink X8 (Parent)
    • Switch
    • TotoLink X8 (Child) (two connected through Ethernet)

Goal:

  1. Separate Network in Basement: I want to set up a private network in the basement using OpenWRT.
  2. IPv6 Support: This private network should also have IPv6 connectivity.

ISP IPv6 Information:

  • IPv6 prefix: /56

Problem:

  • When I connect my OpenWRT router to the switch (which connects to TotoLink), it shows Upstream IPv6 on /64 but doesn’t delegate to OpenWRT.

What I've Tried:

  • Connecting OpenWRT to the switch directly.

Question:

How can I achieve a private OpenWRT network in my basement with IPv6 support, considering my current setup?

Any advice or suggestions would be greatly appreciated. Thank you!

Additional Context:

When I was using a Velop system with the original firmware on the same network structure, it provided IPv6 when I set it to "Passthrough" mode. However, after installing OpenWRT on the Velop to create a subnet, it no longer provides IPv6.

Any ideas on why this change might be affecting IPv6 delegation and how I can resolve it?

Thanks again for your help!

If the upstream router is not capable of handing out a Prefix (PD) then you you can use IPv6 Relay mode:
https://openwrt.org/docs/guide-user/network/ipv6/configuration#ipv6_relay

Maybe the upstream router cannot hand out prefixes at all but it surely cannot if it only has a /64 prefix.

You can try to set the upstream router to request a /60 (or /62) prefix so that it can hand out a /64 prefix to a downstream router

How can I know if it does?
Here is pictures of the TotoLink IPv6 settings.

It is set to Native DHCPv6 now:

Another connection Type:

Never used totolink so perhaps ask at the totolink forum?

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Any help :slight_smile:

It's already been explained to you for conventional v6 routing to work you need a separate routable prefix-- not just a plain /64 address assignment-- from upstream. And since upstream here is not an OpenWrt router, it's outside the scope of this forum.

Also already explained is that when you do have only a /64 you can use what OpenWrt calls relay mode-- which is the same as what others might call passthrough mode. The same /64 can be relayed or passed down through any (reasonable) number of routers. In this case all of the endpoint devices on the network, regardless of their position in the router hierarchy, will have a unique IPv6 but it will be within the same /64. This is a workable solution though not ideal.

1 Like

Hi mk24, thank you for your reply in both threads.

So what is my options if I want to achieve my goal which is :

  1. Separate Network in Basement: I want to set up a private network in the basement using OpenWRT.
  2. IPv6 Support: This private network should also have IPv6 connectivity.

Should I change the upstream routers to one that support DHCPv6 PD? or maybe changing the network structure since my ISP modem support prefix /56 ?

Assuming that the HG8245Q still provides DHCPv6-PD with a reasonable prefix size, the easy solution would be to replace the X8 with an OpenWrt supported device (and ideally the switch with a managed one, if it isn't already, as that allows you a trunk connection with multiple VLANs managed by your router) you can actually configure in terms of prefix sizes and -distribution (the X8 may still act as AP, but it seems to be unsuitable to provide DHCPv6-PD).

Thank you all, I managed connect my basement eth to ISP modem and now I got IPv6 !

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