hardMultiple ChoiceObjective-mapped
300-410 Practice Question: Runs the following command on Router R1: R1# show…
A network engineer runs the following command on Router R1:
R1# show crypto ipsec sa
interface: Tunnel0
Crypto map tag: DMVPN, local addr 10.1.1.1protected vrf: (none) local ident (addr/mask/prot/port): (172.16.0.0/255.255.255.0/47/0) remote ident (addr/mask/prot/port): (172.16.0.0/255.255.255.0/47/0) current_peer 10.1.1.2 port 500 PERMIT, flags={origin_is_acl,} #pkts encaps: 150, #pkts encrypt: 150, #pkts digest: 150 #pkts decaps: 145, #pkts decrypt: 145, #pkts verify: 145 #send errors 0, #recv errors 0
local crypto endpt.: 10.1.1.1, remote crypto endpt.: 10.1.1.2 path mtu 1500, ip mtu 1500, ip mtu idb Tunnel0 current outbound spi: 0x12345678(305419896) PFS (Y/N): N, DH group: none
Based on this output, what is the problem?
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
✓
There is packet loss on the IPsec tunnel.
The output shows IPsec SA details for a DMVPN tunnel. The protect identity uses GRE protocol (47) and the SA is between two spoke routers (172.16.0.0/24). The packet counts show 150 encapsulated but only 145 decapsulated, indicating packet loss on the tunnel. This could be due to MTU issues or routing problems.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
There is packet loss on the IPsec tunnel.
Why this is correct
Encaps count (150) is higher than decaps count (145), indicating loss.
- ✗
The IPsec SA is using PFS.
Why it's wrong here
PFS (Y/N): N indicates PFS is not used.
- ✗
The tunnel is not encrypting traffic.
Why it's wrong here
Encrypt/decrypt counts are non-zero, so encryption is happening.
- ✗
The remote peer is 10.1.1.1.
Why it's wrong here
Remote peer is 10.1.1.2, not 10.1.1.1.
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
Related to this question
Learn chapter
Introduction to ENARSI Exam and Network Fundamentals
Key term
MPLS Layer 3 VPN
A technology that uses Multiprotocol Label Switching to create secure, scalable virtual private networks that connect multiple sites at the network layer, where the service provider manages routing between customer sites.
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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.