With rapid development of the Internet, Internet surfing has been an important daily activity for peoples. There are many websites and web pages containing obscene and malicious information such as phishing, spam and pornography that peoples can easily obtain. In order to improve network security service, the authors developed and implemented a content-based filter system on an embedded Linux home gateway. They analyzed and compared two feasible approaches that the content-based filter was respectively embedded into user space and kernel space of Linux home gateway.