You can configure their computer to have a bogus proxy server address. This can also
be done via Group Policy. You will also need to prevent user from accessing
connection properties. Keep in mind that doing such will only prevent them from using
Internet Explorer to access the internet, but not necessarily prevent them from
accessing the internet with other applications if they have the ability to install
them on their computers. Another way to consider is using a firewall or internet
appliance to deny access based on computers ip address that will need to be
static/reserved or within a dhcp scope that would be denied access or even not
configuring the computer with a default gateway as long as they do not have ability
to modify tcp/ip settings. --- Steve
