CND Practice Question: Network Security Controls Protocols And Devices
A network engineer is configuring IPsec site-to-site VPN policies. During Phase 2 negotiations, which TWO parameters must match identically on both VPN peers for the security association (SA) to establish successfully? (Choose two)
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
✓
IPsec Encapsulation Mode (Tunnel mode or Transport mode)
Phase 2 (IPsec) negotiations require agreement on encapsulation mode (Transport/Tunnel) and the cryptographic transform set (encryption and integrity algorithms). Pre-shared keys and Diffie-Hellman groups for Phase 1 are handled in Phase 1 (IKE).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The physical interface speed (e.g., 1 Gbps vs 10 Gbps) of the WAN ports
Why it's wrong here
Interface speed affects throughput capacity, but IPsec cryptographic SAs are independent of physical line speed.
- ✓
IPsec Encapsulation Mode (Tunnel mode or Transport mode)
Why this is correct
Both peers must agree on whether Tunnel or Transport mode is used for encapsulation.
- ✗
The local device hostname configured in the router's global configuration
Why it's wrong here
Hostnames are local identifiers and do not need to match for IPsec negotiation.
- ✗
The SNMP community string configured on the management plane
Why it's wrong here
SNMP settings are unrelated to IPsec VPN cryptographic parameter negotiations.
- ✓
IPsec Transform Set (Encryption and Integrity algorithms, e.g., AES-256 and SHA-256)
Why this is correct
Both peers must agree on the exact encryption and integrity algorithms used to protect data payloads.
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
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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 EC-Council exam blueprint
This CND practice question is part of Courseiva's free EC-Council 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 CND exam.