Review: 6 slick open source routers
DD-WRT, Tomato, OpenWRT, M0n0wall, PfSense, and Vyatta suit a wide range of devices and networking needs
OpenWRT is a router firmware project that's like a full-blown Linux distribution for embedded systems. You can download the packages for a specific hardware configuration and build the code for that hardware using a supplied tool chain. This complicates the deployment process, but also provides enormous flexibility.
To save time, various prebuilt versions of OpenWRT are available for common hardware types and router platforms. This includes everything from generic x86-based systems to the Broadcom and Atheros chip sets used to power many open-firmware routers. The makers of OpenWRT recommend starting with an off-the-shelf version, then learning how to roll your own once you've found your footing.
Supported hardware: Lots. More than 50 hardware platforms and 10 CPU architectures are supported: everything from ARM mini-boards to full-blown x86-64 systems. They also have a buyer's guide for helping you choose proper hardware for your particular needs, in the event you're shopping for something specifically OpenWRT-compatible.
Features: In addition to broad hardware and platform support, OpenWRT includes support for the OLSR mesh networking protocol, which allows you to create mobile ad hoc networks out of multiple OpenWRT devices. Also, the software, once deployed, can be modified without reflashing the firmware. Packages can be added or removed as needed through a built-in package management system.
Various spin-offs of OpenWRT also exist, some with highly specific usage scenarios. The Cerowrt build, for instance, was created as part of the Bufferbloat project to address network bottlenecking issues in LANs and WANs. FreeWRT is even more developer-focused than the core OpenWRT builds, but has a handy Web-based image builder for those who want to create a FreeWRT firmware with a little guidance. And Gargoyle offers as one of its big features the ability to set bandwidth caps per host.
Limitations: The biggest strengths of OpenWRT are also its biggest limitations. It's best used by people who really, really know what they're doing. If you just want to replace your stock router firmware with something a little more current, steer clear.
Recommendation: OpenWRT is best suited for experts. This is the firmware for people who want as few limitations as possible on what they can do, are ambitious about using unusual hardware, and feel comfortable with the kind of tinkering that would normally go into rolling one's own personalized Linux distro.