IMHO, the best thing to do is to restrict these PCs by simply using access-lists. With an access-list you can block specific IPs and/or ports. If you go that way, one thing to not forget is that one access-list is always created. This access-list denies all IPs on all ports and is always the last one checked.
Routers and/or firewalls also have network identification capabilities.
As to having authentication before using browsers, you can activate, with IE, the access control (french translation) found under internet tools in contents tab. As for other browsers, I have no idea if such options are available.
If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.
Control Internet Usage
I have a problem here wondering if there is any solution to it.
I have an unlimited broadband access that is connected automatically using a router for my network.
Hence by running browser programs such as IE, Netscape, I am able to access Internet via "non-filtered" (Internet accessible) PCs.
My problem is:
I want to control in such a way that user must input id or password in order to run those browser program.
THanks