Baffling DNS problem limited to the USB NIC

[froginperil]

Distro: Fedora
8814au: rtl8814au/5.8.5.1, 6.2.8-200.fc37.x86_64, x86_64: installed

I created a connection restricted to the USB NIC. It connects just fine but I get no name resolution (I can ping an IPA).

There is no error message in the journal or dmesg. iwconfig yields:

wlp0s20f0u1u1 IEEE 802.11AC ESSID:"SBF2.4-5" Nickname:"WIFI@RTL8814AU"
Mode:Managed Frequency:5.24 GHz Access Point: 9C:53:22:99:7B:C3
Bit Rate:867 Mb/s Sensitivity:0/0
Retry:off RTS thr:off Fragment thr:off
Power Management:off
Link Quality=74/100 Signal level=69/100 Noise level=0/100
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
I have tried automatic name resolution and specific DNS servers.

On the same machine, a connection using the internal NIC works perfectly with either automatic or manually entered DNS servers.

[morrownr]

@froginperil

I am in the process of moving right now. If nobody else is able to help, ping me again in about a week,

@morrownr

[froginperil]

Never mind. The culprit is the systemd-resolved service (I think). I don't know if this is limited to Fedora. System-resolved creates a link to /etc/resolv.conf which is recreated every time the service is started. That creates a nameserver at 127.0.0.53 which leads to either the WAN DNS or alternative servers, in my case 127.0.0.1. Disabling the service and creating a legacy static resolv.conf solves the problem.

I have no clue why the new service-driven scheme is deemed better other than to consume some developer's idle time. It adds complexity and another service. Moreover, it is undependable.