go get -v -u git.scc.kit.edu/KIT-CA/dfn-domain-validation-check
Copy the contents of contrib/ to /etc/systemd/system on the target system (as root). Edit
dfn-domain-validation-check.service and change the commandline options to match your CA. Run systemctl daemon-reload
followed by systemctl enable --now dfn-domain-validation-check.timer.