Help for my RPi - wireless interface disappeared

[nprampage]

The issue I am facing:
A couple of days ago, my wlan0 interface disappeared from my Raspberry Pi 3b+ after it had been in place working fine for months. RPi is on Bullseye, Pihole has been updated to the current release that came out this week. The result of this is that my guest wireless network, which uses Pihole via the RPi's wireless network (while my main LAN uses the "main" network interface via Ethernet), was seemed to be very slow or failing at resolving DNS.

After poking around the RPi with ifconfig, I discovered the wlan0 interface was gone. I brought it back by running

dtoverlay=pi3-enable-wifi

and rebooting

Details about my system:
My debug log is https://tricorder.pi-hole.net/Xfjv9Ypr/
I run unbound as a recursive resolver.

I did some reading of basic network interface setup to try and address the issue. Several things pointed to /etc/network/interfaces, which in my case only points to the interfaces.d directory; that directory is empty.

Obviously the setup for my network interfaces is in a different location, but I don't know where that is.

What I have changed since installing Pi-hole:
Many things, but everything was working as expected until this week. I'm not looking for anything but to understand what changed in my setup that could make the wlan0 interface go away.

Any pointers or lessons would be appreciated!

[Bucking_Horn]

This is about a (hardware) detail of a Raspberry Pi.
Creating an additional post at the RaspberryPi forum may get you quicker and more knowledgeable answers.

If you are running your RPi under Raspberry Pi OS, then most probably dhcpcd is handling network address assignment.
Since you state using Bullseye, it could instead be NetworkManager that you'd have to consult for network configuration settings (but only if you'd explicitly enabled that via raspi-config).

In past releases (pre 5, I think), Pi-hole could have installed dhcpcd as a dependency on non-Raspbian systems and altered your /etc/dhcpcd.conf if you'd opted for creating a static IP address during installation, but it has since ceased from doing so.

If it's not related to IP address assignment, then you'd have to consider other s/w and h/w failures as well - but those are also not related to Pi-hole.

I hope this helps to get you started on your issue.

[nprampage]

Thanks for the tip! That’s exactly the kind of lead I was looking for.