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350-401 Practice Question: Which three statements about IPsec VPNs are true?…
Which three statements about IPsec VPNs are true? (Choose three.)
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
✓
IKEv2 is more resilient to network changes than IKEv1 because it supports Dead Peer Detection (DPD) as a built-in feature.
IPsec VPNs can operate in transport mode (protecting payload only) or tunnel mode (protecting entire IP packet). IKEv2 is more robust than IKEv1, supporting EAP authentication and built-in DPD. AES is a symmetric encryption algorithm used for data confidentiality. SHA is used for integrity, not encryption. IKE uses UDP port 500, not TCP. ESP can provide both encryption and authentication, but authentication is optional in some implementations.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
IPsec transport mode encrypts the entire original IP packet, including the IP header.
Why it's wrong here
Incorrect because transport mode only encrypts the payload (transport layer and above), leaving the original IP header intact.
- ✓
IKEv2 is more resilient to network changes than IKEv1 because it supports Dead Peer Detection (DPD) as a built-in feature.
Why this is correct
Correct because IKEv2 includes DPD as a standard mechanism to detect peer liveness, whereas IKEv1 requires separate configuration.
- ✓
AES is a symmetric encryption algorithm commonly used in IPsec to provide data confidentiality.
Why this is correct
Correct because AES is a symmetric cipher used in IPsec for encrypting data; it is widely supported.
- ✗
IKE uses TCP port 500 for key exchange and negotiation of security associations.
Why it's wrong here
Incorrect because IKE uses UDP port 500, not TCP.
- ✓
ESP in tunnel mode can provide both encryption and authentication for the entire IP packet.
Why this is correct
Correct because ESP tunnel mode encrypts the entire original IP packet and adds a new IP header; authentication (integrity check) can be included.
Quick reference
AAA Protocol Comparison
| Protocol | Port(s) | Encryption | Transport | Primary Use |
|---|---|---|---|---|
| RADIUS | 1812 / 1813 | Password only | UDP | Network access control |
| TACACS+ | 49 | Full packet | TCP | Device administration |
| Diameter | 3868 | Full session | TCP / SCTP | Carrier / mobile networks |
| 802.1X | — | EAP-based | Layer 2 | Port-based access control |
TACACS+ encrypts the entire packet; RADIUS only encrypts the password field — a key exam distinction.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-401 practice question is part of Courseiva's free Cisco 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 350-401 exam.