OpenWrt
lastmod 2025-04-17created 2022-09-142 edits
OpenWrt is a Non-Real-Time, Linux-based, open-source operating system for wireless LAN routers.
Development originally began as a custom operating system to enhance the performance of Linksys's WRT54G series of home wireless LAN routers; it later gradually added support for other wireless LAN routers and now supports most router platforms. Embedded boards that provide wireless LAN router functions usually have limited processing power and memory, so it is impossible to implement every Linux feature as on a regular PC, and only the features essential for a router must be selectively installed. OpenWrt offers users convenience by providing the Linux features needed for wireless LAN routers as packages. Early on, OpenWrt was maintained separately as the release version White Russian and the development version Kamikaze, which were merged into Kamikaze in February 2007.
Features
OpenWrt provides by default the many functions offered by the firmware built into typical gateway devices, such as DHCP service and wireless security features like WEP, WPA, and WPA2. In addition to these basic functions, it also provides the following features not offered by stock firmware.
- Port forwarding for external traffic coming into computers behind NAT.
- UPnP for dynamic port forwarding.
- Static DHCP assignment.
- Powerful firewall and router configuration.
- QoS settings for VoIP, online gaming, and multimedia streaming services.
- The device can be configured in various ways, such as a wireless repeater, AP, or wireless bridge. These configurations can also be combined.
- Mesh networking
- Dynamic DNS for users of ISPs that do not provide a static IP.
- Command-line access via SSH or telnet
- On devices with USB ports, support for various connectable devices such as printer sharing, Windows-compatible file sharing (SAMBA), and USB audio.
- Real-time network monitoring
- Powerful AJAX web interface.
- Most importantly, regular bug fixes and updates. Also supports devices that the manufacturer no longer supports.
Another great advantage of OpenWrt is that the file system can be used freely. Using a package management system called ipkg (opkg in recent versions), users can freely install various software and use OpenWrt in a wide variety of ways. Other Linux-based firmware generally uses a read-only file system such as SquashFS, so if users want to add new software, they must rebuild the entire firmware image and flash it. This is OpenWrt's biggest advantage over other Linux-based firmware. Depending on the distribution policy, OpenWrt can build images with either read-only SquashFS or read-write JFFS2, whichever is appropriate.