Network Security and ACLs

Introduction and Objectives

This lab demonstrates essential network security functions from the CCNA I-II level. It focuses on VLAN segmentation, securing switch ports, and applying Access Control Lists (ACLs) to control communication between different network segments. Each chapter builds on the previous one — starting with VLAN configuration and basic device protection, continuing with port-security, and finishing with ACL implementation on the router. The result is a secure and well-segmented network that shows the main purpose of this lab.

Objectives are:

• Configure VLANs and assign switch ports to the correct segments

• Implement basic device security including console passwords and MOTD banner

• Apply port-security to prevent unauthorized devices from accessing the network

• Configure extended ACLs to control inter-VLAN communication

• Verify connectivity and access control between VLANs

Lab Structure

1. VLAN and Basic Device Security

2. Securing Switch Ports

3. Access Control Lists

Key Features

• VLAN segmentation for User, Guest, and Admin networks

• Device and port protection using security features and violation modes

• Extended ACLs controlling inter-VLAN access

• Troubleshooting of a sticky MAC issue affecting Admin connectivity

• Verification confirming correct ACL operation

Author’s Note

This lab integrates the main security concepts from CCNA I into one topology. It demonstrates how VLANs, port-security, and ACLs work together to protect network traffic. Solving an unexpected sticky MAC issue made the process more realistic and showed how security features interact across network layers.

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