A server technician is installing a new server and configuring the newly installed OS. Which of the following steps should be performed FIRST after booting the OS?

Creating a backup before hardening preserves an insecure baseline and offers no protective value at this stage of deployment.

Addressing security concerns - applying patches, disabling unnecessary services, and configuring host-based firewalls - before connecting to any network ensures the OS is not vulnerable during its first moments of operation. Connecting to a network with an unpatched OS creates an immediate attack surface that adversaries can exploit. NIST SP 800-123 explicitly recommends hardening the OS prior to network exposure.

Connecting to the network before hardening exposes an unpatched OS to network-borne threats and violates secure deployment sequencing.

Joining a domain requires network connectivity and presupposes a secured OS, so it cannot logically precede security hardening.