Firewalls
Firewalls Overview
Firewalls are essential network security devices that monitor and control incoming and outgoing network traffic based on predefined security rules. They act as a barrier between trusted internal networks and untrusted external networks, such as the internet.
Key Functions
- Packet Filtering: Firewalls examine network packets and allow or block them based on source and destination IP addresses, ports, and protocols.
- Stateful Inspection: Stateful firewalls track the state of network connections and allow only legitimate traffic to pass through.
- Network Address Translation (NAT): Many firewalls include NAT functionality to translate private IP addresses to public IP addresses.
- Intrusion Prevention System (IPS): Some firewalls include IPS capabilities to detect and block malicious network traffic.
- VPN Support: Many firewalls support virtual private networks (VPNs) to provide secure remote access.
Common Firewall Types
- Hardware Firewalls: Dedicated physical devices that provide high-performance firewall protection.
- Software Firewalls: Software applications installed on computers or servers.
- Next-Generation Firewalls (NGFWs): Advanced firewalls that include features such as application control, intrusion prevention, and deep packet inspection.
Configuration Basics
Firewall configuration typically involves defining security rules that specify which traffic is allowed or blocked. Common configuration tasks include:
- Setting up access control lists (ACLs).
- Configuring NAT rules.
- Enabling intrusion detection and prevention.
- Setting up VPN connections.
- Managing firewall logs.