A) Initiating hosts are then onboarded and authenticated by the SDP gateway

B) Clients on the initiating hosts are then onboarded and authenticated by the SDP controller

C) SDP gateway is brought online

D) Finally, SDP controllers are then brought online The third step in the SDP onboarding process is to onboard and authenticate the initiating hosts, which are the clients that request access to the protected resources. The initiating hosts connect to and authenticate with the SDP gateway, which acts as an accepting host and a proxy for the protected resources. The SDP gateway verifies the identity and posture of the initiating hosts and grants them access to the resources based on the policies defined by the SDP controller. Reference= Certificate of Competence in Zero Trust (CCZT) prepkit, page 21, section 3.1.2 6 SDP Deployment Models to Achieve Zero Trust | CSA, section ''Deployment Models Explained'' Software-Defined Perimeter (SDP) and Zero Trust | CSA, page 7, section 3.1