OpenWrt (from open wireless router) is an open-source project for embedded operating systems based on Linux, primarily used on embedded devices to route network traffic. The main components are Linux, util-linux, musl, and BusyBox. All components have been optimized to be small enough to fit into the limited storage and memory available in home routers.
OpenWrt is configured using a command-line interface (ash shell) or a web interface (LuCI). There are about 8000 optional software packages available for installation via the opkg package management system.
OpenWrt can run on various types of devices, including CPE routers, residential gateways, smartphones, pocket computers (e.g. Ben NanoNote). It is also possible to run OpenWrt on personal computers and laptops.
History
The OpenWrt project was started in 2004 after Linksys had built the firmware for their WRT54G series of wireless routers with code licensed under the GNU General Public License. Under the terms of that license, Linksys was required to make the source code of its modified version available under the same license, which enabled independent developers to create derivative versions. Support was originally limited to the WRT54G series, but has since been expanded to include many other routers and devices from many different manufacturers.
Using this code as a base and later as a reference, developers created a Linux distribution that offers many features not previously found in consumer-level routers. Early on some features required proprietary software. For example, prior to OpenWrt 8.09 (based on Linux 2.6.25 and the b43 kernel module) WLAN for many Broadcom-based routers could only be had via the proprietary wl.o module (and which required Linux 2.4.x).
OpenWrt releases were historically named after cocktails, such as White Russian, Kamikaze, Backfire, Attitude Adjustment, Barrier Breaker and Chaos Calmer, and their recipes were included in the message of the day (motd) displayed after logging in using the command-line interface.
In May 2016, OpenWrt was forked by a group of core OpenWrt contributors due to disagreements on internal process. The fork was dubbed Linux Embedded Development Environment (LEDE). The schism was reconciled a year later. Following the remerger, announced in January 2018, the OpenWrt branding is preserved, with many of the LEDE processes and rules used. The LEDE project name was used for v17.01, with development versions of 18.01 branded OpenWrt, dropping the original cocktail based naming scheme. <noinclude>
Releases
LEDE
The Linux Embedded Development Environment (LEDE) project was a fork of the OpenWrt project and shared many of the same goals. It was created in May 2016 by a group of core OpenWrt contributors due to disagreements on OpenWrt internal processes. The schism was nominally reconciled a year later in May 2017 pending approval of the LEDE developers. The remerger preserves the OpenWrt branding, but uses many of the LEDE processes and rules. The remerge proposal vote was passed by LEDE developers in June 2017, and formally announced in January 2018. The merging process was completed before the OpenWrt 18.06 release.
Features
OpenWrt features a writeable root file system, enabling users to modify any file and easily install additional software. This is in contrast with other firmware based on read-only file systems which don't allow modifying installed software without rebuilding and flashing a complete firmware image. This is accomplished by overlaying a read-only compressed SquashFS file system with a writeable JFFS2 file system using overlayfs. Additional software can be installed with the opkg package manager and the package repository contains approximately 8000 packages (by 2022).
OpenWrt can be configured through either a command-line interface or a web interface called LuCI. OpenWrt provides set of scripts called UCI (unified configuration interface) to unify and simplify configuration through the command-line interface. Additional web interfaces, such as Gargoyle, are also available.
OpenWrt provides regular bug fixes and security updates even for devices that are no longer supported by their manufacturers.
OpenWrt provides exhaustive possibilities to configure common network-related features, like IPv4, IPv6, DNS, DHCP, routing, firewall, NAT, port forwarding and WPA.