Openwrt 21 - router as access point

I have been looking and searching on how to configure a router as an acess point. Since OopenWRT is now on version 21. XX and a couplen things have change there is not straght forward set of instrucions (at least for me ) on how to acomplish this configuration.

Any assistance will be much appreciated.

Set an ip, default gateway and manually specify dns to main router ip (this dns step only if the router itself needs connectivity to download packages) on lan interface.
Then disable lan interface dhcp, connect to main router via lan.


That sounds simple enought, I was waching videos that is what got me confuse.
One more question: What about the firewall, do I leave default?

If you don't use the WAN port, it doesn't matter.

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@frolic reading through the steps I realise I didn't disable DHCPv6 for my AP's. What would be the significance of that?

  1. Disable IPv6 DHCP. Same page, DHCP Server tab again, but click on the IPv6 Settings sub-tab. Set the RA-Service, DHCPv6-Service, and NDP-Proxy dropdowns to disabled.

And sure enough I see an active DHCPv6 lease from one of my AP's. No idea what the significance of this is since I've never understood IPv6 stuff.

One nice thing about the factory firmware for many of the routers is that they tend to have a one-click button for doing all that, including flipping the wan port over to the lan side.

None, really.
APs don't really need IPs, it's just a convince for the network admin.

What's the significance of my APs giving out DHCPv6 leases? Is that bad? Could that cause problems? Giving out DHCPv4 leases is bad right? I would like to understand better the significance here between the two for APs.

If everything is working, none, apparently ,)
Should still disable it, though.

My wife has intermittent iPhone connectivity problems. I always thought it was to do with fast roaming and maybe still is. But could this be related? If anyone else has any explanation relating to DHCPv6 here please chip in!

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As a rule of thumb one should disable DHCP and DNS services on access points. If well configured, APs can have secondary DHCP servers that defer to a main DHCP server on your router (so relaying DHCP requests etc), but I believe one needs to set that, it's not enabled by default.

Let's not hijack someone else's thread please. Open your own.

So if an AP has DHCPv6 enabled and gives out a static lease to a client device can that client device talk with the main router and/or devices connected to the main router? Also does this mean main router and AP will simultaneously offer DHCPv6 leases? What governs priority?

Is the gateway (main router) set on AP effective for IPv6 too?

Rule of thumb (there may be reasons to intentionally configure different scenarios, but those are very rare, and if you'd need those, you'd really know why).

  • the AP is dumb, it doesn't run DHCP or DHCPv6 servers
  • all DHCP/ DHCPv6 leases are managed and handed out by your central router only, the AP merely transports the DHCP packets (like anything else) over the air, but neither modifies them, nor adds its own
  • an AP with active DHCP/ DHCPv6 services really messes up your network, so kill it with fire
    the trick here is not (just) to disable the dnsmasq/ odhcpd initscripts, but to configure them to be disabled (ignore the interfaces) via uci (/etc/config/dhcp), as disabled initscripts will silently re-enable themselves during the next sysupgrade.

Thanks for this.

Just to check: setting ignore under DHCP doesn't disable DHCPv6?

No, that's IPv4-only. Go to the IPv6-Settings of your screenshot and disable odhcpd as well (RA).

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Many thanks. Are both needed to be disabled for DHCPv6 to be disabled?

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Yes, I would also remove the ULA prefix definition from /etc/config/network.


Briefly turning a blind eye to your hijacking (seriously though it is relevant):
Yes, both Apple and Android devices default to using ipv6 if offered by dhcp. But if ipv6 routing to the Internet is not available, the Apple/Android device lingers on ipv6 for a while before trying ipv4.

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Can a LAN device given an DHCPv6 lease access the internet when ISP does not provide IPv6 but only IPv4? If so, presumably one should not only disable DHCPv6 in AP's but also even on main router in this instance?