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Keywords
Internet, Monitoring, Access control, Networks, Management
Abstract
The World Wide Web (WWW) has become an extremely popular information service. Large HTTP packets result in network congestion. Proxy cache servers are widely deployed on the Internet to overcome this obstacle. However, the approach yields an undesirable phenomenon -- a small set of users misuse proxy servers to mirror the entire contents of Web sites. This behavior wastes network resources, increases WWW servers' loads, increases users' waiting time, and violates copyrights. Approaches to designing a proxy server with WWW usage control and to making the proxy server effective on local area networks are proposed to prevent such abnormal WWW access and to prioritize WWW usage. Finally, a system, ProxyBreaker, is implemented to demonstrate the approaches. The implementation reveals that the proposed approaches are effective, such that the abnormal Web access does not reoccur.
Introduction
The World Wide Web (WWW) has become the most popular offering on the Internet because of its ease of use and universal access. In fact, in a study of backbone usage (Thompson et al., 1997), HTTP (Berners-Lee et al., 1996; Fielding et al., 1999) packets comprised two-thirds of all activity, which causes serious network congestion. Proxy cache servers are widely utilized to overcome this obstacle. A proxy server has several significant advantages. First, it reduces waiting time, because remote objects are cached in the local proxy server. Second, it facilitates more efficient use of bandwidth by caching objects that can then be used repeatedly. Third, it shares the load of popular WWW sites, since it acts as a partial reduplication site for the WWW servers. These above advantages, and the lack of WAN bandwidth have encouraged the users of the Taiwan Academic Network (TANet) to use proxy servers. In fact, almost all of TANet's HTTP overseas traffic passes through the proxy cache servers.
A particular event motivated the construction of a proxy server to control abnormal Web usage. In August 1998, a librarian of the National Central University (NCU) received a complaint from the Association of American Physics, stating that a user at NCU downloaded many papers (roughly 900 Mbytes) from their Web site via an NCU's proxy server in a single night. Tracing the access log showed...