Question: During IKEv2 connection initiation for NDS/IP in a Za interface scenario, what action does SEG A (initiator) take upon receiving the remote SEG B's certificate and signature?
Option 1: SEG A immediately verifies the SEG B certificate using its local trust store without further checks.
Option 2: SEG A skips verifying the SEG B signature and proceeds to check the validity of the SEG B certificate.
Option 3: SEG A verifies the remote SEG B signature before proceeding to validate the SEG B certificate through revocation checks and cross-certificate verification.
Option 4: SEG A ignores the received certificate and signature, relying on PSK authentication for the subsequent CREATE_CHILD_SA exchange.
Explanation: This is the correct sequence of actions. Verifying the remote SEG B's signature first ensures the authenticity of the received certificate, which is then further validated through revocation checks and cross-certificate verification to establish trust in the certificate's issuer, ensuring secure connection establishment between the SEGs of different operators.