FireHOL is a

shell script A shell script is a computer program designed to be run by a Unix shell, a command-line interpreter. The various dialects of shell scripts are considered to be command languages. Typical operations performed by shell scripts include file manipu ...

designed as a wrapper for

iptables iptables is a user-space utility program that allows a system administrator to configure the IP packet filter rules of the Linux kernel firewall, implemented as different Netfilter modules. The filters are organized in a set of tables, whi ...

written to ease the customization of the

Linux kernel The Linux kernel is a Free and open-source software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the k ...

's firewall netfilter. FireHOL is free software and open-source, distributed under the terms of the

GNU General Public License The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses, or ''copyleft'' licenses, that guarantee end users the freedom to run, study, share, or modify the software. The GPL was the first ...

. FireHOL does not have

graphical user interface A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such ...

, but is configured through an easy to understand

plain text In computing, plain text is a loose term for data (e.g. file contents) that represent only characters of readable material but not its graphical representation nor other objects ( floating-point numbers, images, etc.). It may also include a lim ...

configuration file. FireHOL first parses the configuration file and then sets the appropriate iptables rules to achieve the expected firewall behavior. It is a large, complex BASH script file, depending on the iptables console tools rather than communicating with the kernel directly. Any Linux system with iptables, BASH, and the appropriate tools can run it. Its main drawback is slower starting times, particularly on older systems. FireHOL's configuration files are fully functional BASH scripts in of themselves.

External links

* * Firewall software Free security software {{linux-stub