While I agree with everyone that this is really a pretty non technical question, I thought I would throw in my two cents anyways. Depending how much effort you really want to go to in order to do this and how recoverable you want it to be, the quickest and easiest to recover mode I can think of is run the following command
sudo iptables -I INPUT 1 -j DROP
If you want to get a little more serious, about it and much harder to fix, find your kernel modules for each NIC or just the NIC's you want to disable and delete them then either rmmod them or reboot the system. You can find the name name of the module by running
ethtool -l eth0
and replacing eth0 with all the NIC's you don't want active. Then to find the kernel modules, let's say in your case your find the driver is e1000e, then run
find /lib/modules/ -iname e1000e | grep '\/kernel\/drivers\/net\/'
That should give you a pretty good view of where the drivers are from there you can delete them if you want though to recover you would need to copy them back from either a package or another backup you made and put them back to where they should be. If for some reason I wanted to disable my NIC in a way that would make sure I couldn't enable it while I was out then I would copy them to a USB fob and leave the fob at home.
Anyways, this is all hypothetical. If you really want to make sure you don't use the net when you shouldn't then you will need to learn to exercise self restraint and personal discipline.
P.S.: If you want to make sure the laptop doesn't access the net again, open it up. If it is a laptop with a WiFi NIC in a mini PCI port then pop it out and throw it away. If it uses an onboard chip for WiFi that is a dedicated chip / it isn't part of the North bridge or South bridge and doesn't provide any other functionality then WiFi then de-solder it and throw it away. If it has WiFi built into a shared chip set then either see if you can disable it in BIOS and have someone else set a BIOS administrator password so you can't change it or just sell the computer and buy one that doesn't have integrated WiFi then go buy some self help books on Getting Things Done and other motivation guides for accomplishing tasks.
https://superuser.com/questions/684005/how-does-one-permanently-disable-gnu-linux-networking – Ciro Santilli 新疆改造中心法轮功六四事件 – 2017-09-30T06:34:51.213
3I... think we don't really got a technical issue here... :) – None – 2011-07-03T20:24:30.147
1Remove the wireless card from the computer (that's still a separate piece, right?) and give it to whomever you'll be turning your thesis in to, with strict instructions not to return it until you show up with your paper. – jwodder – 2011-07-03T20:42:33.853
In most modern laptops; they're not removable. If the OP is running Ubuntu 11.04, it can be assumed that it's a "modern" computer. – bbosak – 2011-07-03T20:44:28.297
Remove network cards and cables, put superglue all over any of the plugs or sockets to prevent cards or cables being reinserted, stop posting inane and useless questions and get on with your work! – Mokubai – 2011-07-03T21:56:21.907
1The "know the su password" can be easily fixed by asking a friend to change it and tell it to you when you finish your important stuff. But frankly, you have to finish some stuff, you have a certain amount of time for that, it doesn't seem to be too big (since you're on SU asking for help) and you even want to waste a part of that precious time for creating artificial limitations for yourself instead of using it to finish writing that boring thesis? Now that's funny, just be a man and write it instead. Or just be a man, don't write it and accept the consequences. This is a valid option too. – vtest – 2011-07-04T02:45:53.137