Within the last two to three months (I’m guessing) Microsoft pushed an update to Windows 10 that breaks OpenWRT wireless functionality.
Symptoms: This seems to be limited to only Windows 10 machines connecting to an OpenWRT AP. The machine connects to the wireless AP, but then shows the dreaded yellow triangle, stating, “no internet, secured” status.
Troubleshooting: I have reset the entire network stack of the machine and all of the other known solutions from Microsoft, but to no avail. I notice on the router (Asus RT-N56U) that the connected radio’s (2.4GHz in this case) physical status light, continues to have a periodic blink (maybe two seconds on, one second off).
This behavior is consistent across multiple Windows 10 machines. It happens in both 15.05 and 18.06 of OpenWRT.
Oddly enough, if I restore firmware back to Asus build everything works just fine. And the indicator light on the router returns to normal.
Prior to the unknown Windows patch, I had been running OpenWRT 15 since its initial release without issue.
Do you have any MAC Address filtering on the router's WiFi, or have all you machines to use only Static Leases? This may conflict with a newer Windows 10 setting "Use Random Hardware Address" under Settings->Network and Internet->Wireless.
Please clarify if the router works ok with other devices than Windows 10 PCs. LED behavior should not depend on the client PCs at all, so it likely indicates something wrong with your config or device support.
What are the system log items related to wifi?
My hunch is that something has changed in the config, and your old wifi config is not usable any more. (e.g. the upgrade to 18.06 and later editing of the config in LuCI has changed something)
I don't have access to the router at the moment as I'm traveling; however, I have run these tests in the past. I get DHCP working and my route on the machine is in fact going though the router (192.168.1.1).
I can't tracert from the Wireless connection (if fails)
same with nslookup
both work from a wired connection or the stock Asus firmware
Yes, the router works for other non-Windows 10 devices (i.e. Apple products). I agree with you on the config hunch, but this is a base default OpenWRT configuration. No settings beyond setting WPA2 and its password. As for the device support, I wonder if this is where the problem truly lies. My main question in that case is why it has worked flawlessly until the last few months?
Which logs specifically would you recommend I review?
Again, the configs are default, stock configs for 18.0.6.
Possibly unrelated but I have seen problem with Win10 networking in general. When I block the port 80 using custom firewall traffic rules, Windows make that network unknown and refuses to talk to the Intranet too. Then it is really hard to remove it from their classification of unknown network. Each version of Win10 has different way of undoing it.