Comment 2 for bug 1992491

Hello and thank you for taking the time to report a bug.

It is not clear from your description what the problem might be. It seems like you're not using systemd-resolved as your resolver, is that correct?

I tried configuring wireguard in a system with and without systemd-resolved active. When systemd-resolved is running, wireguard can successfully adjust /etc/resolv.conf (assuming that there's a DNS entry in the wireguard configuration file). If you choose to disable systemd-resolved and write your own /etc/resolv.conf, you will need to manually invoke the commands to adjust the file yourself. You should also see a warning like this:

[#] resolvconf -a tun.mul -m 0 -x
/etc/resolvconf/update.d/libc: Warning: /etc/resolv.conf is not a symbolic link to /run/resolvconf/resolv.conf

But what you're seeing is different: it seems like your kernel doesn't have the tun interface setup.

Could you please paste the contents of your wireguard configuration file (taking care to remove any sensitive data)?

For what it's worth, we also have an extensive guide explaining how to set up wireguard:

https://ubuntu.com/server/docs/wireguard-vpn-introduction

I am marking this bug as Incomplete for now while we wait for more info from your side. Feel free to mark it as New again when you provide the requested data. Thanks.