Quick Answer
The answer is that the IKE policy is using weak MD5 authentication and DH group 2, both of which are insecure. This is the problem because MD5 is a deprecated hash algorithm vulnerable to collision attacks, and Diffie-Hellman group 2 uses only 1024-bit modular exponentiation, which is no longer considered cryptographically strong. On the Cisco CCNP ENARSI 300-410 exam, this scenario tests your ability to identify weak IKE algorithms in the output of `show crypto isakmp sa detail`, a common troubleshooting command for DMVPN and site-to-site VPNs. A frequent trap is confusing the "Hash" column (which shows the integrity algorithm) with the "Auth" column (which shows the authentication method); here, MD5 in the Auth column is the real security risk, not SHA in the Hash column. Remember the mnemonic "MD5 is Dead, DH2 is Too" to quickly flag these weak IKE policies during the exam.
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. 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.
A network engineer runs the following command on Router R1:
R1# show crypto isakmp sa detail
Codes: C - IKE, M - IKEv2, P - IPsec
C-id Local Remote I-VRF Status Encr Hash Auth DH Lifetime Cap. 1 10.1.1.1 10.1.1.2 ACTIVE aes sha md5 2 86400 2 10.1.1.1 10.1.1.3 ACTIVE aes sha md5 2 86400
Based on this output, what is the problem?
The IKE policy uses weak authentication (MD5) and DH group 2.
MD5 and DH group 2 are cryptographically weak.
The IKE SAs are not active.
Why wrong: Status is ACTIVE.
The IPsec SAs are missing.
Why wrong: This command only shows IKE SAs.
The lifetime is too short.
Why wrong: 86400 seconds (24 hours) is standard.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
The IKE policy uses weak authentication (MD5) and DH group 2.
The output shows IKE phase 1 SAs with encryption aes, hash sha, authentication md5, and DH group 2. The problem is that MD5 is used for authentication, which is considered weak and insecure. Modern DMVPN deployments should use stronger algorithms like SHA-256. Additionally, DH group 2 is weak.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
The IKE policy uses weak authentication (MD5) and DH group 2.
Why this is correct
MD5 and DH group 2 are cryptographically weak.
Related concept
Read the scenario before looking for a memorised answer.
The IKE SAs are not active.
Why it's wrong here
Status is ACTIVE.
The IPsec SAs are missing.
Why it's wrong here
This command only shows IKE SAs.
The lifetime is too short.
Why it's wrong here
86400 seconds (24 hours) is standard.
Common exam traps
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
This command only shows IKE SAs.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which 300-410 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
DMVPN — This question tests DMVPN — Read the scenario before looking for a memorised answer..
The correct answer is: The IKE policy uses weak authentication (MD5) and DH group 2. — The output shows IKE phase 1 SAs with encryption aes, hash sha, authentication md5, and DH group 2. The problem is that MD5 is used for authentication, which is considered weak and insecure. Modern DMVPN deployments should use stronger algorithms like SHA-256. Additionally, DH group 2 is weak.
Identify which 300-410 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 18, 2026
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.
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