Saturday, 25 August 2007

SIP on this - easy VoIP on your N800

In case it passed you by, there's an easy way to make standard SIP calls on your Nokia N800.

All you need to do is head for
http://rtcomm.garage.maemo.org/
to download Nokia's Internet Communications Software update and follow the instructions.

Once it's up and running you can load details of your existing SIP VoIP provider, and make calls to the PSTN using your N800. This is great for those people who's ISP give them free SIP minutes every month included in their Internet package, or those who already pay for a SIP based VoIP service and want to use it on their N800 as well.

OK, so it's been possible to make SIP calls from the N800 for a while now using Gizmo Project software, but lets face it, the Gizmo implementation on the N800 is rubbish. The first 10 seconds or so of every call are lost, and it all goes through Gizmo so if you are trying to do fancy stuff with SIP and Asterisk it didn't work anyway. And that interface! Oh, please!

Come to think of it, I haven't tried anything fancy yet using Nokia's SIP software, but it certainly works well for simple voice calls to the PSTN, which is good enough for me, and not bad for beta software. Now I can use my free SIP minutes on my N800, and then switch to Skype when they run out.

It's a shame that the Nokia address book is so feeble, but what the heck - free phone calls that work using the N800 can't be bad!

Friday, 3 August 2007

Using the aircrack-ng suite on the Nokia N800

Aircrack-ng is a suite of applications that together can crack most WEP keys. (In fact it can be used as part of a WPA attack too, but that's another matter.)

The main problem with the aircrack-ng suite on the N800 is that you can't do packet injection. This means that to crack a WEP key you have to wait around until enough traffic passes over the WEP protected link to crack the WEP key. If injection did work, you could effectively create the traffic you need yourself in a few minutes.

But you can use the suite on the N800 to crack WEP. Try this after installing aircrack-ng and wirelesstools. You can also get both (and possibly more up to date versions) from Collin Mulliner's repository, which you can get details of at http://www.mulliner.org/nokia770/

1. Start Xterm, and become root.

Then enter:
airodump-ng wlan0

This will show you what networks are around, and the MAC addresses of the access points and computers which are connected, and what channels they are operating on. Make a note of the channel of the access point you want to test (ie your own one)

(Note: A fault somewhere in the N800 - perhaps the wifi driver? - means that you'll also see some phantom access points that don't exist, and you may see access points mis-described as having WPA2 when in fact they are using WEP. Nothing you can do about that though. I think this is less of a problem or does not happen at all on the N770 but I have never tried it so I don't know for sure. )

2. Now quit airodump-ng by doing a control c , then restart it by typing

airodump-ng -c X -w mycapture --ivs wlan0

but change the X for the channel number of your access point. This will start capturing data which you will use to crack the WEP key, in a file called mycapture-01.ivs in your home directory

3. Now you have to wait for a while, till you have captured enough data to crack the WEP key. If the access point is busy then you might not have to wait too long.

Anyway, after an hour or so, you can try cracking it.

Type:

aircrack-ng mycapture-01.ivs

and hope for the best. Aircrack will try to crack the key, and if you have enough data captured it should crack the key eventually. If not, it will keep trying, as you gather more and more data, until you are successful (or never if you are unlucky, or if there is not enough traffic on the network)

The latest version of aircrack-ng (0.9.1) has been compiled for the N770 / N800 and this includes the new PTW wep attack. The PTW attack, which you activate by using the -z option when you use aircrack-ng, can crack keys with far far less captured traffic than the default attacks that aircrack-ng uses without the -z option, but sadly it only works on traffic captured as a result of a certain method of packet injection, and as the Nokias don't support packet injection you can't use it.

(If you want to test it on the N800, use a capture file generated by traffic injection using aireplay-ng, part of the aircrack-ng suite, from another computer. If you have such a capture file, say injection.cap, you can transfer it to the Nokia tablet and test it by typing:

aircrack-ng -z injection.cap

and you should get the key very swiftly indeed. The easiest way to do traffic injection is to get a laptop with a suitable wifi card, and then download the BackTrack2 iso, which you can burn onto a CD and run as a LiveCD. It has drivers patched for packet injection so it should work with supported cards "out of the box")

One more thing: think very hard before cracking someone else's access point as this probably illegal and could get you in trouble in many countries. Best stick to your own AP. You don't want to end up in chokey now do you?

Thursday, 2 August 2007

Aliases - using .profile to improve your life

Sick of typing

cd /home/user/MyDocs/.documents

every time you want to navigate to the documents folder on your Nokia N800 using xterm? Sick of typing any long commands?

The good news is you don't have to if you don't want to. You can easily create your own commands, or aliases, which carry out long command line operations like the one above.

All you need to do is create a text file called .profile, which you store in the home directory, /home/user/

In this file, you list your aliases, like this:

alias docs='cd /home/user/MyDocs/.documents/
alias home='cd /home/user/
alias cls='clear'
alias msfc='/home/user/framework-3.0/msfconsole'

and any other commands you want to make aliases for.

Once you restart xterm, (make sure it's the latest version), you'll have these commands at your disposal. In other words,

typing

docs

will execute the command

cd /home/user/MyDocs/.documents/

leaving you with more time to play golf, swim, search for the ultimate grits, or whatever else takes your fancy.

Which is nice.

How do you make a text file? There's lots of ways to do this, but one easy way is to download MaemoPad using the application manager.

So:

1. Download MaemoPad and start it up

2. Go to File New to create a new file

3. Type in your aliases, as described above.

4. Save the file in your documents folder, giving it any name you like, such as aliases. You can't save a file in MaemoPad with a dot at the beginning of the name, so don't bother trying to name it .profile - it won't let you

5. Now we are going to move the file you just made into the /home/user directory, which is where it has to go, and rename it. Start up xterm, and type

mv /home/user/MyDocs/.documents/aliases /home/user/.profile

6. Pause to reflect that that was the last time you will ever have to go through the tedious process of typing "/home/user/MyDocs/.documents/" thanks to your new .profile file, restart your xterm, and go and have some healthy outdoor fun.
 
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