350-401 Network Assurance Practice Question
A network administrator is analyzing syslog messages from a Cisco Catalyst switch and notices the message %SW_MATM-4-MACFLAP_NOTIF: Host 0000.1111.2222 in vlan 10 is flapping between port Gi1/0/1 and port Gi1/0/2. What is the most likely cause of this message?
⚠ Common exam trap
The trap here is immediately blaming spanning tree without considering that a dual-homed device or duplicate MAC can also cause the same symptom.
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 device with MAC address 0000.1111.2222 is connected to both Gi1/0/1 and Gi1/0/2, possibly via a loop or a dual-homed connection.
The %SW_MATM-4-MACFLAP_NOTIF message indicates that the switch has detected the same MAC address being learned on two different ports within a short period. This is most commonly caused by a loop or a device connected to multiple ports, leading to inconsistent MAC address table entries. The administrator should investigate the physical connections and spanning tree topology.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A loop exists in VLAN 10 due to a misconfigured spanning tree.
Why it's wrong here
While a loop can cause MAC address flapping, the message specifically indicates the same MAC address is appearing on two different ports. A spanning tree loop would typically cause broadcast storms and multiple MAC flaps, but the root cause could also be a duplicate MAC address or a misconfigured device. However, the most direct cause is often a duplicate MAC address or a device connected to two ports.
- ✓
A device with MAC address 0000.1111.2222 is connected to both Gi1/0/1 and Gi1/0/2, possibly via a loop or a dual-homed connection.
Why this is correct
This is the most likely cause. The switch is learning the same MAC address on two different ports, which indicates the device is either connected to both ports (e.g., via a loop or a misconfigured NIC teaming) or there is a loop in the network. The switch detects the flapping and generates the syslog message to alert the administrator.
- ✗
The switch has a software bug causing incorrect MAC address learning.
Why it's wrong here
While software bugs can cause unexpected behavior, MAC address flapping is typically a network topology or configuration issue, not a bug. The message is a standard notification designed to alert administrators to a real problem. Assuming a bug without investigating the topology is not a best practice.
- ✗
The MAC address 0000.1111.2222 is configured as a static MAC address on two different ports.
Why it's wrong here
Static MAC addresses are manually assigned and cannot be learned on multiple ports simultaneously. If a static MAC is configured on one port and the same MAC appears on another, it would not cause flapping; instead, it might cause a security violation. This scenario is less likely because static MACs are not dynamically learned.
Visual reference
Quick reference
Access Control Model Comparison
| Model | Acronym | Who Controls Access? | Best For |
|---|---|---|---|
| Discretionary Access Control | DAC | Resource owner | Small teams, file shares |
| Mandatory Access Control | MAC | System / security labels | Classified govt / military |
| Role-Based Access Control | RBAC | Administrator (via roles) | Enterprise environments |
| Attribute-Based Access Control | ABAC | Policy engine (user + resource attributes) | Fine-grained, dynamic policies |
| Rule-Based Access Control | RuBAC | System rules / ACLs | Firewall rules, network ACLs |
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
This 350-401 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 350-401 exam.