Bug #23035
open“DNS Settings” built-in technique doesn't work with systemd-resolved (notably Ubuntu 22.04 LTS)
Description
The “DNS Settings” built-in technique doesn't work for distros using systemd-resolved, which means a number of recent distros including Ubuntu 22.04 LTS.
root@lab_test_2_zgent7:/etc# lsb_release -d
Description: Ubuntu 22.04.2 LTS
When using systemd-resolved, resolv.conf is a symlink to a tmpfs file :
root@lab_test_2_zgent7:/etc# ll resolv.conf
lrwxrwxrwx 1 root root 39 Jun 16 02:07 resolv.conf -> ../run/systemd/resolve/stub-resolv.conf
This makes a directive based upon the “DNS Settings” built-in technique to fail.
With systemd-resolved, the DNS settings are supposed to be in
- /etc/systemd/resolved.conf
- /etc/systemd/resolved.conf.d/dns_servers.conf
etc.
It is also quite probable that the “DNS Settings” built-in technique wouldn't work properly along with other common DNS helper programs such as dsnmasq or resolvconf, that either manipulate the resolv.conf file or symlink it to virtual/temporary files under their own control.
The resolv.conf file is also frequently edited / modified by NetworkManager, common on RedHat like distros and default on many others.