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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  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, 192.168.1.1) 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.

Recovering from a bad flash

Occasionally, a flashing attempt goes bad, leaving the router "bricked" -- that is, the router seems to be starting up, but otherwise doesn't provide network access and management pages are unreachable. Another common symptom: The power light on the front panel of the router flashes nonstop.

Fortunately, a flash problem is rare, and there are ways to recover from it. First, try a hard reset, or a "30/30/30" as the DD-WRT folks (and others) call it:

  • Disconnect the router from the network and hold the hardware reset button for 30 seconds.
  • Keep the reset button held down and remove the power cord for 30 seconds.
  • Plug the power back in and keep holding reset for 30 seconds.
  • Let go of the reset button and unplug the power one last time for a minute or so. Restore power.

This resets the router to its factory default state, which is sometimes needed to get it to boot properly after a flash. If that doesn't work, then you'll need to look into one of the more advanced recovery procedures listed on the DD-WRT and OpenWrt wikis. These include recovery via the aforementioned TFTP or JTAG. A truly wizardly hacker might add his own boot logic (such as Micro Redboot) to this mix, especially if he plans on trying out a variety of different firmware options.

DD-WRT and OpenWrt extras

A full breakdown of the most immediately useful features in DD-WRT or OpenWrt would require a book -- and might be redundant, considering many of those features are common to most routers. However, here's a sampling of features included with DD-WRT and OpenWrt that might not be present on other routers.

  • Boot wait. When enabled, the router pauses for five seconds at boot time to allow the user to connect remotely and flash a new firmware if the current one is bricked. Leave this on, as you never know when it will be useful -- and what's five measly seconds out of a reboot cycle?
  • Logging. DD-WRT and OpenWrt can maintain running logs of its most crucial events and behaviors. The log can either be kept locally or written to a remote IP address that has a syslog daemon listening on the appropriate port. This can be left off by default, but it's useful to toggle it on if you need to do any detailed troubleshooting (for instance, to find out if a specific action is messing up operations).
  • Overclocking. Some routers support the ability to overclock, or run the CPU faster than the manufacturer normally recommends. There are few cases where this is a good idea, especially since overclocking any hardware often leads to instability.
  • Scheduled reboot. You can force the router to reset itself at a given time of day, after a certain interval, or on a specific day of the week. Some claim this improves performance, although in my own experience it doesn't seem to make much difference. The documentation (linked above) shows you how to do this via a command line, but some builds -- including the one in my Buffalo router -- let you set this in the GUI under Administration/Keep Alive. Note that in order to use this, you'll need to enable the Cron option as well.
  • Telnet. The telnet daemon should be running if you plan on connecting via telnet to perform administration (such as to manually flash new firmware). If you're worried about the security implications of leaving telnet running, you can shut it off until you need it.
  • Transmit power and antenna gain. These let you control the power to the wireless antenna and the amount of gain or "focus" used to single out weaker signals. Most of the time these options should be left as-is, but you can experiment with the gain function to see if it improves reception in your environment. Note that increasing transmit power can cause some routers to overheat, so don't fool with it, then forget about it.
  • Watchdog. If enabled, the router will attempt to ping other computers regularly and will reboot itself if it doesn't receive a response. This should not be needed in most environments, but it can be useful if you have a flaky network gateway. Just be sure to use sane intervals for the pings -- anything less than five minutes is probably overkill -- and make sure you're pinging an item for which inaccessibility will be a sure sign of trouble (Google, for instance, or your ISP's home page).
  • Asterisk. This one's for the truly ambitious. Asterisk is an open source PBX system that can be used as a replacement for a proprietary PBX, although the capacities available to Asterisk will be limited by the hardware you're using.

Last words for DD-WRT and OpenWrt users

Once you have your setup running the way you want, keep a few final details in mind for smooth sailing in the future:

  • Back up your router settings every so often. DD-WRT lets you save your router's settings to a file that can be stored on a PC, then reloaded into the router if needed. (OpenWrt has similar functionality.) If you have a number of custom settings -- port forwarding, for instance -- and need to do a 30/30/30 reset, it would be good to have all of it backed up so that you don't have to manually punch it in again.
  • Set passwords. Not just for your wireless connection -- be sure to use WPA2 if your clients can support it -- but also for the administration panel in your firmware. It should go without saying, but designate a different username and password for the admin panel than the out-of-the-box settings. If you stick with the default credentials, your network is a sitting duck.
  • Check for updates about once a month. Bookmark the page where updates for your router are posted, and check it every so often for new versions of the firmware. There's not much point in using a custom firmware if you're not keeping it current.
  • Finally, if it ain't broke, don't fix it. This may sound counterintuitive, but if your main reason for picking up a custom-powered router is stability and functionality, don't shoot yourself in the foot by tinkering with it too much. If you do tinker, back up your settings before trying anything particularly adventurous.

Of course, if you're using a custom firmware explicitly in order to tinker with it, that's another story!

This article, "Teach your router new tricks with DD-WRT or OpenWrt," was originally published at InfoWorld.com. Follow the latest developments in networking and open source at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.

Read more about networking in InfoWorld's Networking Channel.

Serdar Yegulalp is a senior writer at InfoWorld, focused on the InfoWorld Tech Watch news analysis blog and periodic Test Center reviews. Before joining InfoWorld, has written for the original Windows Magazine, Information Week, the briefly resurrected Byte, and a slew of other publications. When he's not covering IT, he's writing SF and fantasy published under his own personal imprint, Genji Press. Follow him on Twitter at @syegulalp and Google+.

This story, "Teach your router new tricks with DD-WRT or OpenWrt" was originally published by InfoWorld.

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