Comment 13 for bug 1774632

I just encountered this issue upgrading Ubuntu MATE from 22.04 to 22.10. After the update, I had no network connectivity, and /etc/resolv.conf was symlinked to /run/systemd/resolve/stub-resolv.conf. I changed that to /run/systemd/resolve/resolve.conf, and my system is able to make connections once again. My system is running NetworkManager, and the only active connection is Docker0.

/run/systemd/resolve/stub-resolv.conf:

nameserver 127.0.0.53
options edns0 trust-ad
search DOMAINS

/run/systemd/resolve/resolv.conf

nameserver 192.168.2.1
nameserver 1.1.1.1
nameserver 1.0.0.1
search DOMAINS

[UPDATE]
After posting this, I found the following post about manually configuring DNS servers with systemd:

https://wiki.archlinux.org/title/systemd-resolved#Setting_DNS_servers

My Ubuntu MATE 22.10 does not have /etc/systemd/resolved.conf.d/dns_servers.conf, but it does have /etc/systemd/resolved.conf. So, I updated that with my DNS entries like so:

DNS=192.168.2.1 1.1.1.1 1.0.0.1

And I reset the /etc/resolv.conf symlink back to /run/systemd/resolve/stub-resolv.conf. Following a reboot, DNS is now working properly. There are a lot of moving pieces here, but it *appears* that to manually configure DNS servers, editing /etc/systemd/resolved.conf (or /etc/systemd/resolved.conf.d/dns_servers.conf if you have it) is the appropriate thing to do.