Requiring a logon to access Internet

We would like to find some method in IE 5.0 to require a NT domain login before users can access the Internet. A registry hack requires local users to logon to the network.

However remote users are not required to logon to allow them to work offline. These remote users can access the Internet without logging onto the network.

We used to enforce a network logon using Microsoft’s Proxy Server. However it required Internet application, browser or winsock changes that were difficult to maintain in addition to it masking the identity of the user in our firewall and web filter logs. Proxy Server is not an option because of it.

We would like something that was transparent to the user.