Adventures in Wireless Networking

This post is a little technical, but even non-techies might benefit from this, since it could theoretically save you some hair-pulling…

So I have a nice agreement with my neighbors next door to share their internet connection with them for $10/month.  That way I save some money, but more importantly, I don't have to wait in my apartment for the slack-jawed yokels at the cable/phone companies to come hook me up with broadband.  It's a sweet arrangement.

Anyhow, everything has been working great, except that I wanted to install Linux (Kubuntu, if you're curious) on PC as well, and I couldn't get my USB Wireless card to play nice with Linux. I wasted a LOT of time on this, until eventually I decided to cough up about $60 for a wireless game adapter, meant to be used with a Playstation 2 or something.  The idea is that it connects your computer/gaming console (which only has a wired connection) to a wireless network.  This was a perfect solution for me, since Linux was very happy with my wired card, just not my wireless card.

But… (of course there's a but) I couldn't connect for some reason.  I was able to get into the gaming adapter and configure it, and that was able to detect the router properly, but it wouldn't go past that point.  The passphrase that I'd been using until now had worked fine for my wireless card (in Windows, that is), but once I put it into my gaming adapter it didn't work.  In other words, my password wasn't working.

So here's where I learned something new/annoying about Wireless security.  When you enter a passphrase into a router or wireless device, it converts it into a hex key, which is a string of numbers and letters (A through F).  A hex key looks like 1D68D71CE.  As a minor aside, the cheap crappy router that I got my family only lets you put in a hex key (it comes up with a random one for you), so you have to write down this hideous string of characters.  Most routers, on the other hand, let you come up with a word, like “YodaYid”, and it will automatically come up with a hex key that corresponds to that.

However, different manufacturers apparently do the conversion differently, and some don't do it at all.  So the hex key for “YodaYid” is different for Linksys, Netgear, D-Link, etc, etc.  All this conspired against me to prevent me from connecting to my neighbor's router, which is of a different manufacturer than my gaming adapter.

Anyway, I had to enter the hex key manually.  But to do that, I had to figure out what the hex key was, based on my passphrase, since the router configuration didn't show me any hex keys – just the passphrase.  Whew.  Luckily, I stumbled on this discussion, from almost four years ago (what would we do without Google?).  ChrisDAT explained that some manufacturers generate the hex key by taking the ASCII value of each letter in the passphrase.  For example, “ABCDE” would turn into “ 4142434445″, since “A” corresponds to “41”, etc.  So I used an ASCII chart to convert from letters to hex (by hand), put in my new hex key, and it worked!  That was my password :-)

The important thing to note is that my hex key wasn't available anywhere.  I had to rely on my computer knowledge to do the research and make my own ASCII.  So a typical computer user would probably be clueless.  Tech support people explained the hex key problem to me (they have a totally different way of making up a hex key from a passphrase), but they weren't much help beyond that.  I didn't know the make of the router at the time (it's my neighbors', after all), and giving them that would have helped, I guess.  It's still a pain in the butt, though, considering how easy it's supposed to be.  And I guess the only reason Windows works is they know the different tricks, or they try all the different conversions until they get it.  In any case, problem solved.  Time to play with Linux!

–YY

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