IPFire

IPFire is purpose-built to turn a small appliance or spare PC into a dedicated firewall/router, with a strong emphasis on network segmentation (color-coded network zones -- green for trusted LAN, red for the internet-facing WAN, and optional orange/blue zones for DMZ or wireless) configured entirely through its own web interface rather than manual firewall-rule editing. Its Pakfire add-on system extends the base firewall with additional capabilities -- intrusion detection/prevention (Suricata), a VPN endpoint, web proxy and content filtering, and more -- installed as modular packages rather than bloating the base firewall image for users who don't need them. It's built independently rather than derived from a mainstream desktop/server distribution, keeping its attack surface and package set tightly scoped to its firewall/router mission.