Network Security & Troubleshooting
Welcome to Part 2 of the CompTIA Network+ course
This blog post covers two major topics of the Network+ course: Network Security and Network Troubleshooting.
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Network Security
Common Threats and Vulnerabilities
- DoS/DDoS: Attacks that flood a network or system to make it unavailable.
- Phishing: Tricking users into revealing sensitive information via fake communication.
- Malware: Malicious software like viruses, worms, or ransomware that can harm systems.
- Man-in-the-middle (MITM): Intercepting communication between two parties to steal or manipulate data.
Security Devices and Technologies
- Firewalls: Monitor and filter incoming/outgoing traffic based on security rules.
- NAC (Network Access Control): A cybersecurity approach that restricts access to a network by ensuring only authorized and compliant devices and users are allowed to connect.
- IDS/IPS: Detects (IDS) or blocks (IPS) malicious traffic in real time.
- SIEM: Aggregates and analyzes security data from across the network for monitoring and alerting.
Authentication and Access Control
- AAA: A framework for managing user access: Authentication, Authorization, and Accounting.
- RADIUS: A protocol for centralized user authentication and accounting.
- TACACS+: Similar to RADIUS, but separates authentication, authorization, and accounting.
- Multifactor Authentication (MFA): Adds extra layers of security using more than one form of identity verification.
Wireless Security
- WPA2/WPA3: Security protocols for wireless networks, WPA3 being the more secure and modern.
- TKIP: An older encryption protocol, now mostly replaced due to vulnerabilities.
- AES: A strong encryption standard used in WPA2/WPA3 for securing data.
Network Segmentation and Isolation
- VLANs: Logically separate networks to reduce broadcast traffic and increase security.
- Air Gaps: Physically isolated networks with no external connections for maximum security.
- DMZ (Demilitarized Zone): A subnetwork that hosts external-facing services, isolated from the internal network.
Network Troubleshooting
Troubleshooting Methodology
- Identify the problem
- Establish a theory
- Test the theory
- Establish a plan
- Verify functionality
- Document findings
- ping: Tests connectivity between devices.
- traceroute: Shows the path packets take to reach a destination.
- ipconfig/ifconfig: Displays IP configuration on Windows/Linux systems.
- nslookup: Queries DNS to resolve domain names.
- netstat: Displays active connections and listening ports.
Common Issues
- IP conflicts: When two devices on the same network have the same IP address.
- DNS issues: Problems resolving domain names due to misconfigured or unavailable DNS servers.
- Cabling problems: Faulty or disconnected cables can cause intermittent or total network failure.
Author: Bilal Qazi
- Updated: April 16, 2025*
For more, visit my GitHub