When configuring an IPsec tunnel using IKEv2, which THREE parameters are commonly negotiated during Phase 1?
IKEv2 Phase 1 negotiates the encryption algorithm, such as AES-256, to protect the IKE SA itself. This is one of the three commonly negotiated Phase 1 parameters, alongside integrity and Diffie-Hellman group, satisfying the stem's requirement.
Why this answer
During IKEv2 Phase 1 (IKE_SA_INIT and IKE_AUTH), the peers negotiate the encryption algorithm such as AES-256 (option A), which protects the IKE SA itself, making it a core Phase 1 parameter. The authentication method, such as PSK or RSA signatures (option B), is also negotiated and validated in Phase 1 to authenticate the peers and establish trust. The Diffie-Hellman group (option E) is likewise negotiated in Phase 1 to perform the key exchange and derive shared secret keys for the IKE SA.
TCP port selection (option C) is not negotiated in Phase 1 because IKE uses UDP ports 500 and 4500, not TCP. Firewall policy ID (option D) is a local configuration construct and is not an IKEv2 Phase 1 negotiation parameter.
Exam trap
FORTINET-NSE7-SPECIALTY often tests whether candidates can separate Phase 1 (IKE SA) parameters from Phase 2 (IPsec SA) parameters and from local-only configuration — options like 'TCP port' and 'firewall policy ID' are distractors that don't belong to either negotiation.