NextDNS and NetworkManager

A while back, I wrote about installing NetworkManager if NextDNS activate fails to work.

Only… I realised that for some reason on Raspberry Pi (4), WiFi stopped working with the following errors:

Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.2204] device (wlan0): state change: config -> failed (reason 'ssid-not-found', sys-iface-state: 'managed')
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7525] device (wlan0): set-hw-addr: set MAC address to 92:F3:ED:C2:8F:9B (scanning)
Feb 17 11:55:02 tyr NetworkManager[449]: <warn>  [1676631302.7559] device (wlan0): Activation: failed for connection 'superuser.one'
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7562] device (wlan0): supplicant interface state: scanning -> disconnected
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7562] device (p2p-dev-wlan0): supplicant management interface state: scanning -> disconnected
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7577] device (wlan0): supplicant interface state: disconnected -> interface_disabled
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7578] device (p2p-dev-wlan0): supplicant management interface state: disconnected -> interface_disabled
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7579] device (wlan0): supplicant interface state: interface_disabled -> disconnected
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7579] device (p2p-dev-wlan0): supplicant management interface state: interface_disabled -> disconnected
Feb 17 11:55:02 tyr NetworkManager[449]: <info>  [1676631302.7585] device (wlan0): state change: failed -> disconnected (reason 'none', sys-iface-state: 'managed')

The WiFi SSID and password (wpa_supplicant) never changed, so I wasn’t sure what it was. However, as most Pi’s are wired I didn’t pay much attention, until today.

As I had one RPi where nextdns activate worked fine, without NetworkManager installed, and where WiFi worked, I figured there was something evil about NetworkManager (= breaks my WiFi) and NextDNS not actually needing it…

I reverted my changed from my previous post (and removed some extra stuff that was not needed in my case, YMMV):

apt purge -y network-manager dnsmasq-base resolvconf modemmanager ppp ; apt install -y powermgmt-base openresolv ; apt autoremove -y

The powermgmt-base, and modemmanager, ppp parts are likely not needed, but this is just a copy and paste of what I did.

Reboot… And WiFi worked again. However, nextdns activate would still throw an error:

# nextdns activate
Error: NetworkManager resolver management: exit status 5

Going through the source code (yay for open-source) I noticed:

var networkManagerFile = "/etc/NetworkManager/conf.d/nextdns.conf"

That file indeed existed on both RPis that had the activate issue.

I ran the following command…

rm /etc/NetworkManager/conf.d/nextdns.conf

But that still gave the same error. But as I had purged the entire NetworkManager, I didn’t need its lingering config files… So, why not rid ourselves of everything:

rm -r /etc/NetworkManager

And tada… Now activate works fine:

tyr ~ # nextdns activate
tyr ~ #

Go figure ¯\_(ツ)_/¯