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Where Firewalls Run

Published on 
Dec 26, 2023
Exploring Leading Vendors’ Hardened OS in Firewalls

Firewalls are essential security devices that protect networks from unauthorized access and malicious activities. These critical components operate on specialized operating systems (OS) designed to provide robust protection and optimize performance. In this article, we will delve into the world of firewalls and examine the hardened OS employed by some of the industry’s leading vendors. From well-established companies to innovative newcomers, let’s explore where firewalls run and the key characteristics of these operating systems.

1. Fortinet – FortiOS: Fortinet, a prominent player in the cybersecurity industry, powers its FortiGate firewall series with FortiOS. While previous versions of FortiOS were based on a modified version of FreeBSD, recent iterations have transitioned to an internally developed operating system based on the open-source Rocky Linux distribution. FortiOS offers a comprehensive suite of security services, including firewalling, VPN, antivirus, web filtering, and intrusion prevention. It provides organizations with scalable and high-performance network protection.

2. Palo Alto Networks – PAN-OS: Palo Alto Networks, a prominent cybersecurity company, powers its flagship Next-Generation Firewall (NGFW) with PAN-OS. PAN-OS,  is a proprietary, purpose-built operating system designed specifically for Palo Alto Networks’ firewalls. It integrates advanced security features, including next-generation threat prevention, application-aware firewalling, and advanced analytics. PAN-OS offers granular control and visibility over network traffic, enabling organizations to secure their networks effectively.

3. Cisco – Cisco ASA OS: Cisco, a leading networking solutions provider, offers firewalls under the Cisco ASA (Adaptive Security Appliance) and Cisco Firepower Threat Defense (FTD) product lines. These firewalls operate on Cisco ASA OS, a specialized operating system designed for security appliances. While the earlier versions of Cisco ASA OS were based on a modified version of Linux, recent iterations have transitioned to an internally developed hardened OS. Cisco ASA OS delivers comprehensive security features, including intrusion prevention, advanced malware protection, and virtual private network (VPN) capabilities.

4. Check Point Software Technologies – Gaia: Check Point Software Technologies, renowned for its network security solutions, utilizes Gaia as the operating system for its firewall appliances. Gaia is a hardened OS developed by Check Point and is based on SecurePlatform and a hardened version of Linux. It combines the security features of a firewall with an intuitive management interface, providing organizations with effective threat prevention, centralized control, and seamless integration with other Check Point security solutions.

5. Juniper Networks – Junos OS: Juniper Networks, a well-established networking solutions provider, relies on Junos OS to drive its firewall appliances, such as the Juniper Networks SRX Series Services Gateways. Junos OS is a carrier-grade, hardened operating system known for its stability, scalability, and security. Although Junos OS shares some components with FreeBSD, it is a distinct and proprietary operating system developed by Juniper Networks. Junos OS enables Juniper’s firewalls to deliver advanced threat prevention, comprehensive policy enforcement, and secure connectivity.


Firewalls play a crucial role in securing networks against evolving cyber threats. The leading vendors in the industry employ customized and hardened operating systems to power their firewall solutions. Fortinet’s FortiOS , Palo Alto Networks’ PAN-OS, Cisco’s ASA OS, Check Point’s Gaia, and Juniper Networks’ Junos OS are purpose-built operating systems designed to provide robust security, comprehensive threat prevention, and centralized management capabilities. By running on these hardened OS, firewalls enable organizations to fortify their networks and safeguard their critical assets in an increasingly interconnected digital landscape.

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