What is a Firewall? The Foundation of Server Security

What is a Firewall?

A firewall is a security system that monitors and controls network traffic based on predetermined security rules. It creates a barrier between trusted internal networks and untrusted external networks.

How Firewalls Work

1. Packet Inspection: Source IP, destination IP, port, protocol analyzed.
2. Rule Matching: Packet compared against security rules.
3. Decision: Accept, reject, or drop the packet.

Firewall Types

• Hardware Firewall: Physical network device for enterprises.
• Software Firewall: Runs on the OS for servers and PCs.
• WAF: Protects web applications from SQL injection, XSS attacks.

Popular Linux Firewall Tools

Essential Firewall Rules

1. Change default SSH port
2. Open only required ports (80, 443)
3. Apply rate limiting
4. GeoIP blocking

We offer firewall configuration support on our VDS packages.