mediumMultiple Choice
Port Security Violation: Why a Switch Port Goes err-disabled
A security administrator is concerned about MAC address spoofing on the network. Which technology can help mitigate this risk by associating a specific MAC address with a port?
⚠ Common exam trap
ISC2 often tests the distinction between features that prevent MAC spoofing (port security) versus features that prevent ARP spoofing (DAI) or DHCP attacks (DHCP snooping), leading candidates to confuse the purpose of each technology.
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
✓
Port security
Port security is the correct answer because it directly mitigates MAC address spoofing by allowing an administrator to statically or dynamically associate a specific MAC address with a switch port. When a device with a different MAC address attempts to use that port, port security can either disable the port (errdisable) or drop the traffic, preventing unauthorized access. This is a Layer 2 security feature that enforces MAC-to-port binding.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Port security
Why this is correct
Port security binds specific MAC addresses to individual switch ports, so frames arriving with a spoofed source MAC from an unauthorised device trigger a violation action such as shutdown or restrict. This directly satisfies the requirement to associate a MAC address with a port.
- ✗
Dynamic ARP inspection
Why it's wrong here
Dynamic ARP inspection validates ARP packets against the DHCP snooping binding table, mitigating ARP poisoning rather than MAC spoofing on a port. It is tempting because it also uses MAC and IP bindings. Port security is the feature that restricts which MAC addresses may appear on a given port.
- ✗
DHCP snooping
Why it's wrong here
DHCP snooping filters rogue DHCP servers by trusting only specific ports for DHCP offers, but it does not bind a MAC address to a port. It is tempting because it also builds a binding table. Port security is the feature that enforces the MAC-to-port association the scenario requires.
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VLAN hopping prevention
Why it's wrong here
VLAN hopping prevention addresses VLAN tagging abuse, such as double tagging or switch spoofing, not MAC-to-port binding. It is tempting because both are Layer 2 hardening features. Port security is the mechanism that actually associates a specific MAC address with a switch port and blocks violations.
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 |
Go deeper
Related to this question
Learn chapter
Network Security Components and Controls
Key term
MAC
MAC (Media Access Control) is a unique hardware identifier assigned to network interfaces for communication on a local network segment.
Key term
Port security
Port security is a network switch feature that restricts which devices can connect to a port based on the device's MAC address, preventing unauthorized access.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CC practice question is part of Courseiva's free ISC2 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 CC exam.