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Teach your router new tricks with DD-WRT or OpenWrt

Open source DD-WRT or OpenWrt firmware can breathe new life -- and advanced features -- into your old wired or wireless router

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Flashing the router
The next step is to load the router with the firmware, which can be one of the thorniest steps in the process. Here, DD-WRT has a slight advantage in that one can simply pick up a router preloaded with some variety of DD-WRT and not bother with the hassle of flashing. Such routers typically can be updated to the latest edition of DD-WRT with ease, although you'll generally need to obtain updates for those routers from the manufacturer directly. The manufacturer may have hardware-specific adaptations of DD-WRT that you can't find anywhere else, or (like Buffalo) it may have firmware that is encrypted and can run only on that router.

The way to check whether you need an update varies among routers, but the short version goes something like this:

  1. In the router's manual, look up how to access the router's properties/administration pages. This usually involves connecting to a local address (for example, via a Web browser.
  2. Look there for the revision number of the loaded firmware. This might be listed either as a build number (say, 14998), a date (May 25, 2011), or both at once.
  3. Go to the router manufacturer's website and look up the download page for that exact model of router. Router manufacturers often use abominably confusing naming conventions, so read carefully and look for all the details you can. For instance, Actiontec's MI424WR router comes in three hardware flavors: revisions A, C, and D. The most definitive way to find out which router hardware you have is to check the underside or the back for a label that describes the model number.
  4. Check the date on the firmware available for that router against the firmware already loaded. If the available firmware is newer than the preloaded firmware, it's time to upgrade.

The process for flashing a router with DD-WRT firmware will depend on whether the manufacturer supports DD-WRT directly. If so, you can simply download and flash the firmware it provides. The DD-WRT firmware's management page includes a Web interface for uploading and automatically flashing the router, so the process is as simple as a couple of clicks. Just make sure you're feeding the router the correct firmware file.

If the manufacturer does not support DD-WRT, you'll need to look up your router in the DD-WRT wiki and hunt for specific instructions on how to do this. Here, it can get complicated. Some devices require a TFTP flash technique, where you connect to the router via the network and use a Trivial File Transfer Protocol client to upload the firmware. Or consider the flashing directions for the D-Link DIR-615 Rev C router, which requires some hackwork involving a hex editor on the firmware image.

Those who have no fear of a command line and can follow directions closely shouldn't have a problem with the more advanced flashing techniques. If you don't count yourself in that category, you're better off either getting a local guru to do it for you or, once again, dropping the money on a router that has DD-WRT out of the box.

As for OpenWrt, there are four basic methods for flashing firmware: You can use the existing firmware's upgrader to load OpenWrt, use TFTP or a similar technology via an Ethernet port, use TFTP over a serial port, or use the JTAG method, which involves a physical cable connected directly to the router. This last technique is needed for only bare-board, experimental routers or devices that can't be flashed any other way.

In all cases, if there's an option to reset the router to its default settings, use that to make sure no legacy settings are lingering that might create initialization problems.

A number of routers -- such as my Buffalo AirStation -- ship with the manufacturer's own, customized version of DD-WRT, in which case you can update the firmware via DD-WRT's Web interface. Be sure the "After flashing, reset to default settings" option is enabled.
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