Firewalls

Introduction to Firewall

• A firewall is a network security system that controls and filters network traffic, acting as a watchman between a private network and the public Internet.

• They come in two broad categories:
  • Software-based: installed on individual devices for protection
  • Hardware-based: stand-alone devices that safeguard an entire network.
• Firewalls have several types, each designed for specific security needs:
  1. Packet Filtering Firewalls: Examines packets of data, accepting or rejecting based on source, destination, or protocols.

1. Circuit-level Gateways: Monitors TCP handshake between packets to determine session legitimacy.

2. Application-level Gateways (Proxy Firewalls): Filters incoming traffic between your network and traffic source, offering a protective shield against untrusted networks.

3. Stateful Inspection Firewalls: Tracks active connections to determine which packets to allow, analyzing in the context of their place in a data stream.

4. Next-Generation Firewalls (NGFWs): Advanced firewalls that integrate traditional methods with functionalities like intrusion prevention systems, deep packet analysis, and application awareness.