FORTINET-NSE123 Practice Question: Nse 2 Technical Introduction TO Fortinet Security
When configuring an IPsec VPN tunnel between two FortiGate devices, what is the specific role of Phase 1 negotiation?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
To authenticate the two VPN peers and establish a secure management channel (ISAKMP SA)
IPsec Phase 1 establishes a secure, authenticated communication channel (ISAKMP SA) between two peers, negotiating encryption, hashing, authentication methods, and Diffie-Hellman groups.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
To assign dynamic virtual IP addresses to remote SSL VPN client workstations
Why it's wrong here
Virtual IP address assignment is an SSL VPN feature, not part of IPsec Phase 1.
- ✓
To authenticate the two VPN peers and establish a secure management channel (ISAKMP SA)
Why this is correct
Phase 1 negotiates authentication and security parameters to build the IKE SA channel.
- ✗
To encrypt actual user data packets traversing the VPN using IPsec ESP protocols
Why it's wrong here
Data encryption parameters for user traffic are negotiated during Phase 2.
- ✗
To perform DNS name resolution for remote peer public IP addresses
Why it's wrong here
DNS resolution happens independently before VPN negotiation begins.
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
About these practice questions
This FORTINET-NSE123 question is part of Courseiva's 296-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Fortinet exam blueprint
This FORTINET-NSE123 practice question is part of Courseiva's free Fortinet certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the FORTINET-NSE123 exam.