A network security administrator is deploying a site-to-site Virtual Private Network (VPN) using Internet Key Exchange version 2 (IKEv2) and IPsec. Place the following operational phases and message exchanges in the correct chronological order from the first step to the final step during successful tunnel negotiation and data transfer.
- 1The VPN peers exchange IKE_SA_INIT messages to negotiate cryptographic algorithms, exchange nonces, and perform a Diffie-Hellman key exchange.
- 2The VPN peers exchange encrypted IKE_AUTH messages to verify peer identities using certificates or pre-shared keys.
- 3The IPsec Child Security Association (Child SA) parameters are finalized to specify operational encryption and integrity algorithms for data payloads.
- 4User network traffic is encapsulated using Encapsulating Security Payload (ESP) and routed securely through the active IPsec tunnel.
Answer
The correct chronological sequence for establishing an IKEv2/IPsec VPN tunnel is: 1) Negotiate cryptographic parameters and Diffie-Hellman keys via IKE_SA_INIT, 2) Authenticate peer identities via encrypted IKE_AUTH exchange, 3) Finalize the IPsec Child Security Association parameters, and 4) Transmit encapsulated payload data across the established tunnel.
IKEv2 establishes secure IPsec tunnels in a structured sequence: First, the IKE_SA_INIT exchange negotiates security algorithms and generates Diffie-Hellman key material. Second, using the encrypted channel formed by the initial exchange, the IKE_AUTH exchange authenticates peer identities (via certificates or pre-shared keys). Third, the specific IPsec Child Security Association parameters are negotiated. Finally, user network traffic is encapsulated using ESP and safely routed across the tunnel.
Step-by-Step Solution
Key Concept
IKEv2/IPsec Tunnel Negotiation Sequence