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| Developer(s) | Eric Garver, Thomas Woerner,Red Hat, Inc. |
|---|---|
| Initial release | January 3, 2011; 14 years ago (2011-01-03)[1] |
| Stable release | |
| Repository | github |
| Written in | Python |
| Operating system | Linux |
| Platform | Netfilter |
| License | GNU General Public License 2 |
| Website | www |
firewalld is afirewall management tool forLinux operating systems. It provides firewall features by acting as a front-end for the Linux kernel'snetfilter framework. firewalld's current default backend isnftables. Prior to v0.6.0,iptables was the default backend.[3] Through its abstractions, firewalld acts as an alternative to nft and iptables command line programs. The namefirewalld adheres to theUnix convention of naming systemdaemons by appending the letter "d".[4]
firewalld is written inPython. It was intended to be ported toC++, but the porting project was abandoned in January 2015.[5]
firewalld supports bothIPv4 andIPv6 networks and can administer separatefirewall zones with varying degrees of trust as defined inzone profiles. Administrators can configureNetwork Manager to automatically switch zone profiles based on knownWi-Fi (wireless) andEthernet (wired) networks, but firewalld cannot do this on its own.[6]
Services and applications can use theD-Bus interface to query and configure the firewall.[7] firewalld supports timed rules, meaning the number of connections (or "hits") to a service can be limited globally. There is no support for hit-counting and subsequent connection rejection per source IP; a common technique deployed to limit the impact of brute-force hacking anddistributed denial-of-service attacks.[8]
firewalld's command syntax is similar to but more verbose than otheriptables front-ends likeUbuntu'sUncomplicated Firewall (ufw).[8] The command-line interface allows managing firewall rulesets for protocol, ports, source and destination; or predefined services by name.
Services are defined asXML files containing port- and protocol-mappings, and optionally extra information like specifyingsubnets and listing required Kernel helper modules.[9]The syntax resembles that ofsystemd's service files. A simple service file for a web server listening onTCP port 443 might look like this:
<?xml version="1.0" encoding="utf-8"?><service><short>WebServer</short><description>PublicwebhostoverHTTPS.</description><portport="443"protocol="tcp"/></service>
firewalld v0.9.0 added native support for forward and output forwarding via policy objects.[10] This allows filtering traffic flowing between zones. Policies support most firewalld primitives available to zones: services, ports, forward-ports, masquerade, rich rules, etc.
By default firewalld does not block outbound traffic as required by standards such as NIST 800-171 and800-53. However, an outbound block can be added with a policy.
firewall-config is a graphical front-end that is optionally included with firewalld, with support for most of its features.
firewall-applet is a small status indicator utility that is optionally included with firewalld. It can provide firewall event log notifications as well as a quick way to open firewall-config. firewall-applet was ported from theGTK+ to theQt framework in the summer of 2015 following theGNOME Desktop’s deprecation ofsystem tray icons.[11]
firewalld ships by default on the following Linux distributions:[7]
firewalld is enabled by default in all of these distributions. firewalld is also available as one of many firewall options in the package repository of many other popular distributions such asDebian[13] or Ubuntu.
