[SOLVED] No internet access on Windows 11 client

[hyperreal]

I have an OPNsense router I purchased from Deciso B.V. On my main workstation, I dual boot between Fedora Linux and Windows 11. When I'm booted into Windows 11, I can't get Internet access even though it says I'm connected. Only a few sites will load in the web browser, such as Google, Facebook, GitHub, but other sites won't, such as this forum and other non-big tech sites. I can also ping these sites with no packet loss but not other non-big tech sites.

I disabled the wired ethernet adapter in Windows device manager, and then connected to a different Wifi network that is on a separate line and different ISP, from which I was able to get Internet access. However, I'm able to get Internet access from my OPNsense LAN while booted into Fedora Linux. I can also get Internet access when using USB tethering from my phone. So I think this narrows it down to a Windows-specific issue with my OPNsense setup. The weird thing is that this was working fine, and I was able to get Internet access on Windows, a few days ago. Since I'm connected to my LAN, I'm able to access the OPNsense web UI from the web browser in Windows, but access to and from the WAN is degraded or doesn't work.

There was a Windows update on April 12th that seems to coincide with the time this problem began. I can't uninstall this update though because it's not uninstallable in the Windows settings menu. But as I indicated, I don't think it's *entirely* a Windows-specific issue because I can get Internet access when connected to another Wifi network, nor do I think it's *entirely* and OPNsense issue because everything works fine when I'm booted into Fedora Linux.

Things I've tried to no avail:
- Resetting the network adapters to defaults from the Windows settings menu
- Reinstalling the Windows network drivers for my hardware
- Reinstalling Windows 11
- Disabling the firewall on OPNsense to see if it's a packet filtering issue and nope, it's not.
- Rebooting the OPNsense device

I've tried using a separate DNS server for that DHCP client, which didn't seem to help either, but I haven't really given this a thorough inspection. I can perform nslookups on the big tech domains mentioned above from Windows and they seem to resolve fine, but my own domain doesn't resolve or ping. After I post this I will boot back into Windows and attempt a more thorough inspection of DNS.

Please let me know if there is any other info needed about my setup.

[hyperreal]

An update on this:

So I've realized that it seems to only affect HTTP(S) traffic. On Windows 11, I can SSH into my remote VPS using both the IP address and the domain that points to it, but I cannot access the web server running on that VPS from the web browser. The error I get in the browser is a request timeout or sometimes connection reset. curl (or Invoke-WebRequest) from PowerShell hangs when I attempt to access that URL.

The weird thing is that other sites from big tech corps work. I can access Facebook, Google, Microsoft, and GitHub just fine. I'm not sure what to make of that. I recall a long time ago having an issue where the network I was on only allowed IPv6 traffic, and those same big tech sites were the only ones I was able to access from the browser. I tried running Mullvad VPN, because I was able to download the package from GitHub since I could access GitHub from the browser, but it couldn't connect to mullvad.net, and the error it gave said something to the effect of "api.mullvad.net is blocked, please check your firewall".

When I boot back into Windows again, I'll check the IPv6 settings. My OPNsense device is not configured to use IPv6 though.

[hyperreal]

So I was able to resolve this by resetting OPNsense to its factory defaults. The 20 minutes of reconfiguration was better than spending longer trying to figure out what's causing the issue. I've scoured my firewall rules and settings and everything was exactly how it's supposed to be. I don't know I must have monkeyed around with something that caused HTTP(S) to break on Windows even though I'm pretty sure I didn't. I'm still not sure what happened and I think it's best if I not dwell on the possibilities.