The development of the Internet over the past few years has led to new requirements for controlling access to files, data, and other material made available on campus networks. Like many institutional networks at colleges and universities, PennNet (the University of Pennsylvania campus network) is primarily an open network. Access to most of its resources and material is freely available to anyone on the Internet. Some providers of information, however, have had reasons to restrict access to network resources either to members of the university community only or to specific individuals. Securing the subset of these resources that are available through Web interfaces is the topic of this article.