: Filtering software is the most commonly used to protect children and young people from illegal and harmful contents on the Internet. Most of this software blocks access to Internet site that contains information such as pornography, violence, drugs, gambling, and so on, using black list filtering (BLF) method. In this method, filter uses the encrypted huge black list at client PC. BLF, accordingly, causes three major problems: black list updating, black list security, and performance degradation of client PC, because of the encrypted huge black list. In this paper, we describe a new method called access list filtering on client/server (ALFCS). The method can solve all of the three problems of BLF and improve filtering performance. The main idea is to use the small access list at client PC, and if needed, query to black list server to use the huge black list. Experiments of this method show that we achieve significant filtering speedup as compared to BLF without any performance degrad...