I have wasted the last 2.5 hours trying to see where I went wrong with my configuration and I just can't.

For the record, I am running OpenSuse Tumbleweed with Gnome, latest update for everything. Up to now I have been using AdGuard as my DNS resolver, but am now trying to switch to Mullvad but at this point I think I probably don't want to anymore. Reason being, I just can not get it to work for the life of me.

My system has NetworkManager installed so I go there, select my connected Wifi, and enter Mullvad's DNS address 194.242.2.4 in thr IPv4 section, then I go to check to see if it shows I am using their DNS and it Firefox AND Vivaldi give no internet connection errors. I go back to Adguard DNS and my internet is back working again. I go back to Mullvad, you guessed it, no internet once again. I even tried Cloudflare and Quad 9's DNS addresses and both of those worked as well but Mullvad's just does not want to work and I am going insane over it.

And no I can not edit resolv.conf through the terminal because NetworkManager will override it and no I don't want to delete NetworkManager. Any feedback would be appreciated.

Edit: I have Mullvad DNS on my phone and got it running with zero issues so this is more of a Linux problem than a Mullvad DNS problem I think.

Solution:

Open terminal and follow through

sudo zypper install systemd-network

sudo nano /etc/systemd/resolved.conf

Copy paste this into the file that you just opened and change the DNS to whichever DNS provider you are using.

[Resolve]

DNS=194.242.2.4 2a07:e340::4

FallbackDNS=194.242.2.2 2a07:e340::2

Domains=~.

DNSSEC=yes

DNSOverTLS=opportunistic

#MulticastDNS=no

#LLMNR=no

#Cache=yes #CacheFromLocalhost=no

#DNSStubListener=no

#DNSStubListenerExtra=

#ReadEtcHosts=yes

#ResolveUnicastSingleLabel=no

Ctrl + O to write out and Ctrl + X to exit back to the terminal main page.

ln -sf ../run/systemd/resolve/stub-resolv.conf /etc/resolv.conf

sudo systemctl start systemd-resolved

sudo systemctl enable systemd-resolved

sudo systemctl restart NetworkManager

Boom it should be working now.