Network Security

 What Is a Firewall? Types, Features, and Benefits.

A firewall is a network security device that monitors incoming and outgoing network traffic. It applies predefined security rules to determine whether network traffic should be allowed or blocked.

How Does a Firewall Work.

When data travels across the internet, it is divided into packets.

The firewall examines each packet by checking:

Source IP address

Destination IP address

Port number

Protocol (TCP/UDP)

Security Policies.

If the traffic matches allowed rules, it passes through.

If it violates security rules, it is blocked.

Why Are Firewalls Important?

• Firewalls help organizations:
• Prevent unauthorized access
• Block hackers
• Stop malware
• Protect sensitive information
• Monitor network traffic
• Enforce security policies.

Types of Firewalls

1. Packet Filtering Firewall

Checks packet headers only.

Advantages

• Fast
• Low resource usage

Disadvantages

Limited security

2. Stateful Firewall

Tracks active network sessions and makes smarter filtering decisions.

Next-Generation Firewall (NGFW)

NGFW includes advanced capabilities such as:

• Deep packet inspection
• Application awareness

Intrusion prevention

Malware protection

User-based policies

4. Web Application Firewall (WAF)

A WAF protects web applications from attacks such as:

• SQL Injection
• Cross-Site Scripting (XSS)
• HTTP-based attacks

Firewall Best Practices

• Allow only necessary ports.
• Regularly update firewall rules.
• Enable logging and monitoring.
• Review firewall policies periodically.
• Combine firewalls with IDS/IPS solution