Network + 4.3 Network Security Features & Defense Techniques + 5.1 Network Troubleshooting Methodology

Device Hardening

Securing a device by reducing its attack surface.

Disable Unneeded Ports

Shuts down unused switchports to prevent unauthorized access.

Disable Unneeded Services

Removes unused services to reduce vulnerabilities.

Change Default Passwords

Prevents easy compromise using publicly known credentials.

Network Access Control (NAC)

Enforces security policies to allow only compliant devices onto the network.

Port Security

Limits allowed MAC addresses on a switch port.

802.1X Authentication

Port-based authentication using EAP before network access is granted.

MAC Filtering

Allows network access only to approved MAC addresses.

Key Management

Secure handling of cryptographic keys throughout their lifecycle.

Key Rotation

Regularly changing keys to reduce exposure.

Key Revocation

Invalidating compromised or unused cryptographic keys.

Security Rules

Policies controlling network traffic and resource access.

Access Control List (ACL)

Filters traffic based on IP, protocol, and port.

Uniform Resource Locator (URL) Filtering

Blocks or allows access based on website URLs.

Content Filtering

Inspects content to block malicious or inappropriate material.

Network Zones

Logical separation of network areas by trust level.

Trusted Zone

Secure internal network containing critical systems.

Untrusted Zone

External or public network with minimal trust.

Screened Subnet (DMZ)

Buffer network hosting public-facing services between trusted and untrusted zones.

What’s the Network Troubleshoot Methodology?

Identify the problem

Establish a Theory of Probable Cause

Test the Theory

Establish a Plan of Action

Implement the Solution

Verify Full Functionality & Prevent

Document Findings

Establish Theory of Cause

Form logical explanations based on gathered data

OSI Model Approach

Troubleshoot layer-by-layer, top-down or bottom-up.

Divide and Conquer

Isolate sections of the network to pinpoint the fault.