How to create a router that will work on a wireless LAN without internet connection

Hey guys, I want to create a network where I can have other RPI's communicate with eachother in a local network that doesn't have internet access, but still be wireless. I know nothing about networking but wanted to dive right in and see if i could make the project work. I can get a wireless access point to show up, but my devices will not connect to it.

My questions are this:

  1. Is openWRT the correct option for this type of project
  2. How do i have openWRT work as a wireless local area network without internet access.

again, I have 0 experience here and am just curious if this is even possible. thanks for any help

Welcome to OpenWrt @majorsport

Technically, you don't even need a router to do what you want since you won't be connecting them to the internet. However, it can be useful to have a router to act as a DHCP server so that all of your devices can get an automatic IP address assignment. To that end:

Sure. But you don't have to use OpenWrt, either. OpenWrt does allow a lot of features and configuration options that most stock firmware does not -- stuff that might be useful later, but it probably doesn't matter either way for now.

Simple... just don't connect the router to the internet. This isn't a sarcastic/flippant response -- it is simply practical. If you don't want/need internet access for your devices, don't plug in the internet connection into that router. Typically that would go into the WAN port of the router -- you'll just leave that empty. Everything else will work normally, but obviously your devices will not have internet connections.

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If the devices that have trouble connecting are mobile phones, then the reason is they check for an internet connection. Perhaps you can force them to use your network, or you can use the "fake Internet" package.

you can force the phones to stay on the WLAN, even though there's no "internet connection" per their definition, at least Androids.

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I have a similar question, that is not worth a duplicate thread. What if you want a zone like OP described, and a normal LAN zone on the same router?

I have made a setup like this by editing the firewall rules to not allow forward from "restricted LAN" to WAN. This setup have worked flawlessly for months, but a few times I have seen that I have internet connection from inside this "restricted LAN".
I have run packet capture on various interfaces on the router, and see that the packets entering the router from restricted LAN are as expected, but for some reason OpenWrt decides to route them out on WAN, when firewall rules shouldn't allow it.

Is there a way to make 100% sure that a firewall zone / interface can't communicate over WAN?

Post your firewall config file.

Looking through the firewall config, I found one line which I have never noticed before

config forwarding
	option dest 'wan'

I think this must be a leftover from changing names/deleting interfaces. Maybe this could act as a wildcard and allow traffic? I still don't understand why it would work as I intended 95% of the time though.

To add to OP's original question, not allowing a LAN network to forward to destination zone WAN should have the desired effect.