- A
It provides better performance than transport mode
Why wrong: Tunnel mode adds overhead due to encapsulation, so performance is usually worse.
- B
A new IP header is added to the packet
Tunnel mode adds a new outer IP header; transport mode does not.
- C
The entire original IP packet is encapsulated and encrypted
Tunnel mode encapsulates the whole packet, including headers, providing more comprehensive protection.
- D
It is used for end-to-end communication between hosts
Why wrong: Transport mode is typically used for host-to-host; tunnel mode is for gateway-to-gateway.
- E
Only the payload of the packet is encrypted
Why wrong: That describes transport mode with ESP; tunnel mode encrypts the entire original packet.
Question 822 of 1,000
CISSP Communication and Network Security Practice Question
This CISSP practice question tests your understanding of communication and network security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO features are true of IPsec tunnel mode compared to transport mode? (Select 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
✓
A new IP header is added to the packet
In IPsec tunnel mode, the entire original IP packet (including the original IP header) is encapsulated within a new IP packet. A new outer IP header is added, and the entire inner packet is encrypted and optionally authenticated. This is why option B is correct: a new IP header is added to the packet.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It provides better performance than transport mode
Why it's wrong here
Tunnel mode adds overhead due to encapsulation, so performance is usually worse.
- ✓
A new IP header is added to the packet
Why this is correct
Tunnel mode adds a new outer IP header; transport mode does not.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
The entire original IP packet is encapsulated and encrypted
Why this is correct
Tunnel mode encapsulates the whole packet, including headers, providing more comprehensive protection.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
It is used for end-to-end communication between hosts
Why it's wrong here
Transport mode is typically used for host-to-host; tunnel mode is for gateway-to-gateway.
- ✗
Only the payload of the packet is encrypted
Why it's wrong here
That describes transport mode with ESP; tunnel mode encrypts the entire original packet.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that tunnel mode is faster because it 'tunnels' traffic, but the added encapsulation and encryption overhead actually makes it slower than transport mode; the trap is confusing the purpose (hiding internal addresses) with performance characteristics.
Detailed technical explanation
How to think about this question
In tunnel mode, the original IP packet is encapsulated in a new IP packet with a new header (typically with source/destination of the VPN gateways). The entire inner packet is encrypted using ESP (Encapsulating Security Payload) or authenticated using AH (Authentication Header). This allows the original packet's source and destination addresses to be hidden, which is critical for protecting internal network topology in site-to-site VPNs. In contrast, transport mode only encrypts the payload and leaves the original IP header in plaintext, making it suitable for direct host-to-host communication where the endpoints are the IPsec peers.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
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.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this CISSP question test?
Communication and Network Security — This question tests Communication and Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: A new IP header is added to the packet — In IPsec tunnel mode, the entire original IP packet (including the original IP header) is encapsulated within a new IP packet. A new outer IP header is added, and the entire inner packet is encrypted and optionally authenticated. This is why option B is correct: a new IP header is added to the packet.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jul 4, 2026
This CISSP practice question is part of Courseiva's free ISC2 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 CISSP exam.
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