CSF (ConfigServer Security & Firewall) was a popular firewall solution for Linux servers. Since CSF has officially been discontinued as of August 2025, the Sentinel Firewall project continues its development as a fully compatible fork. Sentinel is a drop-in replacement for CSF, providing the same functionality, security, and commands.

This guide covers installing Sentinel Firewall on popular Linux distributions:
- Ubuntu: 22.04, 24.04, 25.04
- Debian: 12, 13
- AlmaLinux: 8, 9, 10
- Rocky Linux: 8, 9, 10
- CentOS Stream: 8, 9, 10