← Back to Courses
Lesson 1: Introduction to Network Security
Page 1 of 2What is Network Security?
Network security consists of policies, processes, and practices adopted to prevent, detect, and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources. Network security involves the authorization of access to data in a network, which is controlled by the network administrator.
Types of Network Threats
| Threat Type | Description | Severity Level |
|---|---|---|
| Denial of Service (DoS) | Overwhelms a system to make it unavailable to users | High |
| Man-in-the-Middle | Attacker secretly intercepts communication between two parties | Critical |
| Phishing | Fraudulent attempt to steal sensitive information by impersonation | Medium |
| SQL Injection | Inserting malicious SQL code into queries to manipulate databases | Critical |
| Packet Sniffing | Capturing and analyzing data packets transmitted over a network | Medium |
Network Security Layers
A comprehensive network security strategy is built across multiple layers:
- Physical Security
- Access control to data centers
- Surveillance cameras
- Hardware locks and biometrics
- Network Perimeter Security
- Firewalls (hardware and software)
- Intrusion Detection Systems (IDS)
- Demilitarized Zones (DMZ)
- Endpoint Security
- Antivirus and anti-malware software
- Patch management
- Device encryption
- Data Security
- Encryption of data at rest
- Encryption of data in transit (TLS/SSL)
- Data loss prevention (DLP)