How can I restrict and control access to my server?

All major servers have features that allow you to limit access to particular sites, and many clients have authentication features that allow you to identify specific users. An overview of this topic available from the w3 Organization web server (URL is <URL:http://www.w3.org/hypertext/WWW/AccessAuthorization/Overview.html> ). There is also a tutorial on security and user authentication with the NCSA server and Mosaic available, written by Marc Andreessen (URL is <URL:http://hoohoo.ncsa.uiuc.edu/docs/tutorials/user.html> ). See your server documentation for further information.
World Wide Web FAQ