Need to block url in all browsers

[Ennio]

I'm wrinting a small program and one of the feature is to block some urls when the user try to go on the web browser.

So I would like to know where can I look for information about how can I do this.

Thank you

[dglienna]

Enter the addresse's in the HOSTS file

[Ennio]

but the problem is that some users have different leves, and they will be able to see some websites that others cannot.

So I would have to rewrite the host files everytime a users login in to the computer?

[j0nas]

dglienna solution's is very a pragmatic one. Other solutions probably need lots of development, for instance writing a web or socks proxy with user auth etc.

Maybe you can find a free web proxy that supports Proxy-Authorization on localhost with NTLM auth... (with url blocking support as well of course).

[dglienna]

Buy a Firewall appliance for a business. That's the only way to make sure. Even with hosts file, people can still bypass it if they know how. You'd have a password to bypass the firewall, but, could also have many levels of authentication.

[srelu]

Use this server, it will allow you any kind of user access customization you want. Basically it's a proxy server.
http://www.microsoft.com/isaserver/default.mspx