Firewalls are a primary line of defense for networked environments. With multiple modules Bitninja offers the best defense currently on the market. BitNinja fights against hackers, botnets, attackers, and malicious activities. It is supported on all modern Linux distributions like: CentOS RedHat CloudLinux Debian Debian Ubuntu It is compatible with most of the other 3rd party softwares like CSF, maldet, mod_sec, fail2ban, etc. Easy to install, and to configure, you are up and running in a couple of minutes. Provides support and understandable documentation. The help you to find the best solution for your needs. Continuous Development. New, and complex rule sets used, each of them is tested so low level(almost none) of false positives.

It require almost no modification in your current software and infrastructure, very little impact on performance during normal operation

I've been using bitninja for a while then decided to switch servers but it ran into some issues, the staff worked tirelessly to help me fix it and it was resolved very quickly, the modules are perfect.