If not already in place, install a Nessus scanner on the same host as SecurityCenter. It does not need to be started or otherwise configured.
To prevent the Nessus scanner from starting automatically upon restarting the system, run the following command:
# /sbin/systemctl is-enabled nessusd off
Run the following command and save the challenge string that is displayed:
# /opt/nessus/sbin/nessuscli fetch –-challenge