I need help in order to block facebook on some of my school pcs.
Anybody has a clue on how I am supposed to do this?


thnaks for your help

You might get better help if you ask on http://ubuntuforums.org/

if you have a firewall then block it from there.
You can also block them on DNS level if you have schools PCs use same DNS.
Use Ubuntu firewall or hosts file if you have to block it per machine and you don't have a firewall or DNS.

http://www.google.com/search?q=ubunt...0block%20sites

Bog loads of relevant results.

thank ya all i edited the hosts file with help from this guide...

http://www.technama.com/2010/block-w...-ubuntu-linux/

if you have access to the router, then you can block it there. But most stock firmwares don't let you do this stuff. You should block domain name AND the facebook's ip ranges or kids will bypath the block by typing in ip address. Also, I would completely block any type of VPN/SSH connections(by packet inspection, not just by blocking standard ports), to prevent any attempts of tunneling through another internet.

You have a difficult problem ahead of you.

There are a few ways you can do it, but by far the easiest is to install a transparent proxy (like squid) on a server or appliance somewhere in the path.

For https stuff I tend to gather up a list of IP addresses for the domain to block, then use iptables to drop and log the connections.

Install something like squidview and monitor it daily because students will actively try to find alternative methods to access the site. Depending on how many students you have, and how determined they are, it'll probably take a week or two to clean it up to the point where everyone gets the message that facebook is not allowed. This wont stop them trying, but it'll stop the majority.

Another way is to add 0.0.0.0 facebook.com to the /etc/hosts file - but they'll figure out how to circumvent that quicker than you can blink.