wirelezz blog

waves're in the air everywhere I look around…

What is so great about OpenWRT?

with 3 comments

Lately I’ve been experimenting with OpenWRT, a linux distribution for embedded devices. The great thing about OpenWRT is that you can install it to most of the cheapest WLAN devices, ie. routers (check the table of supported hardware).

I know that most Open Source projects may never be as good as proprietary solutions for real implementations. However, in the particular case of OpenWRT, I have identified three major advantages:

It’s a great tool for research
It’s an awesome tool for researching on many fields such as: protocol design, fast handoff schemes research, WIDS, Wireless mesh networking, and so on. Learning and doing Unix socket programming in C for OpenWRT may give a large number of headaches, but it’s the best way to get the full control of the information sent over the air.

It’s a great study tool
There’s indeed a difference between reading about the 802.11 standard and getting hands-on training equipment -of course, reading is extremely important- but some of the most advanced concepts are not available anywhere but in enterprise solutions. If you don’t have the access to such equipment, you may want to install OpenWRT on your (cheap) Linksys WRT54GL and also install some packages that would do the magic.

For instance, how do you see what is actually going on through a WPA2-Enterprise (with a RADIUS server, EAP/MD5 auth) handshake on both the wired and wireless side? You could install FreeRadius to a linux box to use as authentication server. Sniffing the air is possible by using wireshark or tcpdump in the OpenWRT box.

If you want to learn a little more about WLAN Controllers, you may want to take a look at the ChilliSpot project. You need to install it on both a WRT54G and a Linux box to see it in action.

VLAN segmentation by editing configuration files, deploying a VPN server on the router, wireless mesh networking using different routing protocols, installing Asterisk on the box, etc. There’re A LOT of packages that can be installed.

Save money
It’s as simple as this: you get many of the features only found in (expensive) enterprise solutions by installing a free firmware on a $60 router.

As I said (somewhere) above, OpenWRT may not be suitable for large enterprise implementations (should not), but it’s a great tool for studying the 802.11 standard, researching or just having some fun. I do not recommend it for illegal purposes.

Some useful links:
Installing and configuring OpenWRT Kamikaze
OpenWRT forum
Use FreeRADIUS for Wi-Fi Authentication


The idea of writing this post came up after reading a question asked by @jameyk1stner via Twitter which basically stated: is there any way to practice for the CWNA exam with real scenarios by using real APs, Controllers, etc?.

Written by Wirelezz

August 23, 2010 at 10:15 am

Posted in Uncategorized

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3 Responses

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  1. Thanks for this! I recently purchased 3 Linksys WRT54GS so I can set them up in a mesh with Freifunk. Wish me luck!

    Jennifer

    August 24, 2010 at 1:10 pm

  2. Thanks for the comment! I haven’t got the opportunity to play with Freifunk, but I’ll give a try if running OLSR in OpenWRT starts giving me trouble :)… Good luck!

    Wirelezz

    August 28, 2010 at 6:57 pm

  3. […] In the last post, I wrote about OpenWRT and how it can help you doing some things you can only do with expensive gear… In this case, I’ll write about how to install OpenWRT on your WRT54G. It’s actually not very difficult and there’re a lot of guides that show how to do it, but I wanted to share my experience. I’m going to focus on Kamikaze 8.09, which is a stable version of OpenWRT. Nowadays there’s a more up-to-date version called Backfire, which is yet to be tested and bug-corrected in more depth, so that’s why we’re sticking to Kamikaze. Attention! You’re about to change the firmware of your router, the responsibility of following this guide strictly lays on you. I’m showing the steps that worked for me. In other words: do not sue me if you brick your router, thanks . […]


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