(apple)mac geek

I’m staying at a place where there are about 20 of us sharing a single Telkom 3 GB line…which, needless to say, stopped working 5 days ago when we exceeded our bandwidth. I’ve volunteered myself to install some sort of user management system so we can have individual log-ons to the internet so we can keep track of how much bandwidth each person is using.

The only snag is, I don’t know how to do it! Help! I have 2 ideas currently: SkyRove and Ubuntu. Here goes…

One option is installing SkyRove on our router (I heard the SkyRove guys speak at a 27 Dinner in April last year in Jozi) and issue vouchers to everyone (we don’t want to charge for usage…yet!). This will at least give everyone separate login accounts to the internet once they’ve connected wirelessly – I’m just not sure of the reporting capacities (can I view bandwidth usage per user per month?).

To install SkyRove I’ll either need to buy their router, or install their firmware update on our Telkom router (which I think will support it?).

Another option is to use the edubuntu server I’ve recently set up to somehow connect directly to the internet (via PPPoE?) and then allow access to that connection through the wireless router somehow. I think that means that people will connect to the local wireless network, which will then route them (how?) through the Ubuntu server, which will have a list of users which people somehow authenticate against, and then allow connection to the internet, somehow logging the internet activity. This would be kinda cool, because then I could install a squid proxy server on the line and probably reduce bandwidth usage that way, so I’d be quite happy to do this too.

Any advice from the networking geeks out there?

Technorati Tags: edubuntu, Skyrove

Comments(1)

Often when downloading a file you’ll see a companion optional download – an md5 checksum. That’s a way of verifying that the file you’ve downloaded hasn’t been altered in any way (say, to add a little command to email porn to your mother-in-law every Tuesday at 3am, or a nasty virus infecting you Windows users). Technically-speaking, it’s a one-way hash function – which means that it produces a string of characters from the input file. The function is set up in such a way that if a single part of the file changes, the string produced at the end will be quite different.

THAT all means that you have a way of verifying that you’re not downloading something which will wipe your hard drive at midnight (unless that’s what you’re into). Just run the downloaded file through the same program (called md5sum) and compare the result to the md5 checksum online. If they match, you’re good to go.

Here’s the command to run:

md5sum file-I-hope-isnt-an-evilly-manipulated-program.zip

This will give an output like:

24c1675e1c65e093c8238f77413ed9b2

Compare that to the online string…they should match.

Verifying md5 checksums can also be a useful way of verifying that the edubuntu cd you just burnt from the iso image has burnt properly. In this case, one of the burnt files is md5sum.txt – a list of the md5 checksums of each file on the cd. Verifying each file has burnt properly is a good idea, so that halfway through your new install it doesn’t crash and cause some mild ceiling-staring annoyance, punctuated by what my Dad calls “non-Presbyterian language”. I’ve learnt some cool words from my Dad! But now I use them less because of md5sum (I think there’s a t-shirt in there somewhere…).

So, this is what you do:

cd /cdrom
md5sum -c md5sum.txt | grep -v 'OK$'

If it spits anything out, then there’s a problem. This process has helped me realise my cd writer on my MacBook Pro doesn’t know how to properly write edubuntu cd’s…but luckily my G4 iBook does.

Technorati Tags: edubuntu, md5sum

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I’ve recently downloaded edubuntu so I can install it on a spare PC (its default setup is as a thin-client server – something I want to play with). After downloading the iso, I need to burn it to a cd. Here’s how to do it, courtesy of Mac OS X Hints:

1. Insert a blank disc.
2. Start Disk Utility.
3. From the File menu, choose Open Disk Image and select the ISO to be burned.
4. In the list of volumes, you will now see an item representing the ISO file. Select it.
5. Click the Burn button and follow the instructions.

I also could’ve burnt it from the command line by:

hdiutil burn image.iso

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