mediumMultiple ChoiceObjective-mapped
300-410 Practice Question: Runs the following command to troubleshoot IPsec…
A network engineer runs the following command to troubleshoot IPsec on a DMVPN tunnel:
R1# debug crypto isakmp
ISAKMP: received peer 192.168.1.2, port 500, local 192.168.1.1 ISAKMP: SA created, initiating IKE Main Mode ISAKMP: sent MM_SA proposal to 192.168.1.2 ISAKMP: received MM_SA response from 192.168.1.2 ISAKMP: Main Mode complete, starting Quick Mode ISAKMP: sent QM_SA request to 192.168.1.2 ISAKMP: received QM_SA response from 192.168.1.2 ISAKMP: Quick Mode done, IPsec SA established
What does this output indicate?
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
✓
IKE negotiation succeeded and an IPsec SA is now active.
The debug shows successful IKE Main Mode and Quick Mode exchanges, resulting in an established IPsec SA between 192.168.1.1 and 192.168.1.2.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
IKE negotiation failed; no IPsec SA was established.
Why it's wrong here
Incorrect because the output shows both Main Mode and Quick Mode completed successfully.
- ✓
IKE negotiation succeeded and an IPsec SA is now active.
Why this is correct
Correct: The debug confirms Main Mode and Quick Mode completion, and states 'IPsec SA established'.
- ✗
The peer 192.168.1.2 is not responding to IKE requests.
Why it's wrong here
Incorrect because responses are received.
- ✗
IKE is using Aggressive Mode instead of Main Mode.
Why it's wrong here
Incorrect because the output explicitly mentions Main Mode.
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.
Go deeper
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Same concept, more angles
1 more way this is tested on 300-410
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A network engineer runs the following command on Router R1: R1# show crypto isakmp sa dst src state conn-id slot status 10.1.1.2 10.1.1.1 MM_ACTIVE 1 0 ACTIVE 10.1.1.3 10.1.1.1 MM_ACTIVE 2 0 ACTIVE Based on this output, which statement is correct?
medium- ✓ A.IKE phase 1 is complete for both peers.
- B.IKE phase 2 is complete for both peers.
- C.The IPsec tunnels are established.
- D.The peers are not responding.
Why A: The show crypto isakmp sa command shows IKE phase 1 security associations. The state MM_ACTIVE indicates that IKE phase 1 is complete and active. The output shows two active SAs with the local router (10.1.1.1) and two remote peers (10.1.1.2 and 10.1.1.3).
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.