Lost OpenWrt device on the network?

Well this is weird.

I have 5 OpenWRT APs (i have a complex building). They are 4 Netgear R6220 and one of the "smaller" Netgear WAC-104, which is identical to the R6220 without USB).

Each device exports a 2.4Ghz and 5Ghz network with all same name and Fast Transition enabled.

All five of them works just fine. Wired ethernet works, and also WiFi works just fine. I can see them all five, connect wifi devices and access network perfectly.

Now, four of them (the R6220s) are indoor and i can also access LuCI via ip (let's say 10.0.0.2, 10.0.0.3, 10.0.0.4 and 10.0.0.5). The fifth (the WAC104) is outside (protected by weather elements of course), and... well... i "lost" it... I cannot figure out on which IP it should reply! I tried to ping them all (only 250 such after all...) with no luck. To be clear, all five are connected with wired ethernet toghether.

I unplugged & plugged it back... nothing.
I can access wired devices connected to that AP, as well i can connect over the wifi of that specific AP... so it's working... But where is it??? How do i find it?

(all 4 R6220s are on 19.07, the WAC104 might be on 22.03 i don't remember)

I would get to the DHCP server on the network, then list the clients on it. Not sure whether your dhcp server is openwrt.

Did you tried ping on link local IPv6 as well?

I am ipv6 illitterate... How would i do that?

(Dnsmasq is my DHCP and there is nothing there)

If you have not disabled IPv6 then go to the router where the lost AP is connected too. Wifi or wired does not matter. On the router run ping ff02::1%<name of the interface>. The interface could be br-lan.

Then all devices on that network segment will answer with their link local address. Let it run for like 2 seconds. Then you only need to find the correct one. Filter out the link local addresses of the other devices.
It's manual labor but if you find it you can use it to also ssh to that lost AP....

One reason why I keep a list of these addresses.... Just in case.... You know. Wouldn't be the first time I would need it :sweat:

I did that, i got a nice list of IPv6 addresses...
Now, what do i do with that? I have sorted them and i have 24 of them. By counting the devices i should have, i have one extra (i counted 23 unless i missed one...) so this might lead somewhere... But What do i do with those addresses? If i try to paste to broser i get an error...

To help troubleshoot this you could power down all the other APs so that only the problematic one is active (which might also shorten the list of IPv6 addresses you get)?

Try IPv6 syntax for the URL:

http://[xxxx:xxxx:xxxx:y]/

Only Microsoft edge let you use an LLA on an URL thanks to ****** stupid discussions made up by Firefox and chrome devs.
So the LLA is only useful for ssh in this case.

Back to topic: if you have a bunch of fe80:: addresses, paste them in a text editor, connect to each device, have a look at the link local addresses and remove these from your list. You should end up with only the addresses of your lost ap

Thank you guys... Going the ipv6 ruote i found out that i mistakenly assigned the same ip v4 to two devices and this of course prevented access to the right one. Fixed that and now all is good!

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