Question 1,283 of 2,152
DMVPNeasyMultiple ChoiceObjective-mapped

Choosing Correct IPsec Transform Set Mode: Tunnel vs Transport for DMVPN

This 300-410 practice question tests your understanding of dmvpn. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. A key principle to apply: iPsec Transform Set. 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.

A network engineer runs the following command to verify IPsec transform sets on a DMVPN hub:

R1# show crypto ipsec transform-set

Transform set combined: { esp-aes 256 esp-sha-hmac } will negotiate = { Tunnel, },

Transform set TS1: { esp-aes 256 esp-sha-hmac } will negotiate = { Transport, },

What does this output indicate?

Quick Answer

The correct answer is that transform set 'TS1' is used for DMVPN because it specifies transport mode. DMVPN relies on mGRE tunnels, which already provide the outer IP header for encapsulation, so IPsec should operate in transport mode to avoid double encapsulation—only the payload is encrypted while the original IP header is preserved. On the Cisco CCNP ENARSI 300-410 exam, this concept tests your understanding of how IPsec interacts with DMVPN overlay networks; a common trap is assuming tunnel mode is always correct for VPNs, but DMVPN’s mGRE architecture specifically requires transport mode to maintain routing and NHRP functionality. Remember the key distinction: tunnel mode encapsulates the entire original packet with a new IP header (used for site-to-site VPNs), while transport mode only encrypts the payload, leaving the original header intact. A helpful memory tip is “DMVPN rides on mGRE, so IPsec rides in transport—no extra tunnel needed.”

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

The transform set 'TS1' is used for DMVPN because it uses transport mode.

The output displays two transform sets: 'combined' with tunnel mode and 'TS1' with transport mode. DMVPN uses mGRE tunnels that require IPsec transport mode, as transport mode preserves the original IP header for the mGRE encapsulation. Therefore, the output indicates that TS1 (transport mode) is the appropriate transform set for DMVPN. Option A is incorrect because while both sets use the same algorithms, the key indication for DMVPN is the mode, not the algorithms.

Key principle: IPsec Transform Set

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Both transform sets are configured with the same encryption and authentication algorithms.

    Why it's wrong here

    Both transform sets share the same encryption and authentication algorithms, but this is not the key indication for DMVPN. The critical difference is the mode (tunnel vs. transport), so A is not the best answer.

  • The transform set 'combined' is used for DMVPN because it uses tunnel mode.

    Why it's wrong here

    Incorrect because DMVPN typically uses transport mode.

  • The transform set 'TS1' is used for DMVPN because it uses transport mode.

    Why this is correct

    TS1 uses transport mode, which is required for DMVPN mGRE tunnels. Transport mode encapsulates only the payload, allowing the original IP header to remain for the mGRE tunnel.

    Related concept

    IPsec Transform Set

  • No transform sets are configured; the output is empty.

    Why it's wrong here

    Incorrect because two transform sets are shown.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.

Trap categories for this question

  • Command / output trap

    Incorrect because two transform sets are shown.

Detailed technical explanation

How to think about this question

Treat this as a scenario question. Identify the problem, the constraint, and the best action. Then compare each option against those facts.

KKey Concepts to Remember

  • IPsec Transform Set
  • Transport Mode vs Tunnel Mode
  • DMVPN IPsec Requirements

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

IPsec Transform Set

Real-world example

How this comes up in practice

A practitioner preparing for the 300-410 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. IPsec Transform Set Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.

Quick reference

VPN Protocol Comparison

ProtocolPortEncryptionAuthenticationUse Case
IKEv2 / IPsecUDP 500 / 4500AES-256Certificates / PSKSite-to-site & remote access
SSL / TLS VPNTCP 443TLS 1.3Certificates / MFAClientless remote access
L2TP / IPsecUDP 1701AES (IPsec)PSK / CertificatesLegacy remote access
WireGuardUDP 51820ChaCha20Public keysModern high-performance VPN
PPTPTCP 1723MPPE (weak)MS-CHAPv2Legacy — 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.

Review iPsec Transform Set, then practise related 300-410 questions on the same topic to reinforce the concept.

Related practice questions

Related 300-410 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Practice this exam

Start a free 300-410 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

FAQ

Questions learners often ask

What does this 300-410 question test?

DMVPN — This question tests DMVPN — IPsec Transform Set.

What is the correct answer to this question?

The correct answer is: The transform set 'TS1' is used for DMVPN because it uses transport mode. — The output displays two transform sets: 'combined' with tunnel mode and 'TS1' with transport mode. DMVPN uses mGRE tunnels that require IPsec transport mode, as transport mode preserves the original IP header for the mGRE encapsulation. Therefore, the output indicates that TS1 (transport mode) is the appropriate transform set for DMVPN. Option A is incorrect because while both sets use the same algorithms, the key indication for DMVPN is the mode, not the algorithms.

What should I do if I get this 300-410 question wrong?

Review iPsec Transform Set, then practise related 300-410 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

IPsec Transform Set

About these practice questions

Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

Keep practising

More 300-410 practice questions

Last reviewed: Jun 18, 2026

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

Sign in to join the discussion.

This 300-410 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 300-410 exam.