If you need to give limited access to users on LAN, you can use free proxy software from

http://www.handcraftedsoftware.org

This is a great software, you can have good control on your network and see who is accessing which web site.

There is a simple way to disable access to a web site on all users on the LAN. This is done by editing hosts file on the main PC that connect to internet, normally one with IP 192.168.0.1

On Windows

C\:WINDOWS\system32\drivers\etc\hosts

On Linux

/etc/hosts

Add following

127.0.0.1	yahoo.com

Once this is done, no one on the network will be able to access yahoo.com.

Repeat the same for all sites you need to block.

yahoo is just an example, don’t block yahoo 🙂