Will show that my domain "cyphermox.net" here is not passed from DHCP in networkd to resolved (and does not show in /run/systemd/resolve/stub-resolv.conf or resolv.conf), whereas if I switch the renderer to "NetworkManager", I can then see both ~. and "cyphermox.net" in search domains when running 'systemd-resolve --status'.
I could reproduce this trivially; a simple netplan config:
network:
version: 2
renderer: networkd
ethernets:
eth0:
dhcp: yes
Will show that my domain "cyphermox.net" here is not passed from DHCP in networkd to resolved (and does not show in /run/systemd/ resolve/ stub-resolv. conf or resolv.conf), whereas if I switch the renderer to "NetworkManager", I can then see both ~. and "cyphermox.net" in search domains when running 'systemd-resolve --status'.