Security Fundamentals

Learn how networks are protected using ACLs, AAA, encryption, and device security features.

▶Network Security Overview

Network security protects data, devices, and communication from unauthorized access and attacks.

▶CIA Triad

Confidentiality, Integrity, and Availability are the core principles of security.

▶Common Threats

Malware, phishing, MITM attacks, and unauthorized access.

▶AAA Security Model

Authentication, Authorization, and Accounting framework.

▶Authentication

Verifies user identity.

▶Authorization

Defines user permissions and access levels.

▶Accounting

Tracks user activity and logs actions.

▶Secure Device Access

Methods used to securely access network devices.

▶SSH

Encrypted remote access protocol (replaces Telnet).

▶Telnet (Legacy)

Unencrypted remote access (not secure, deprecated).

▶Password Security

Strong passwords and encryption for device access.

▶Access Control Lists (ACLs)

Rules that filter traffic entering or leaving a network.

▶Standard ACL

Filters traffic based only on source IP address.

▶Extended ACL

Filters based on source, destination, protocol, and ports.

▶ACL Placement Rule

Standard ACL near destination, extended ACL near source.

▶Device Security Features

Protecting switches and routers from unauthorized access.

▶Port Security

Limits MAC addresses allowed on a switch port.

▶DHCP Snooping

Prevents rogue DHCP servers.

▶Dynamic ARP Inspection

Protects against ARP spoofing attacks.