The Design And Implementation Of A Software Firewall Based On Content Filtering

Once the beginning of information society, many information systems have been built in many organizations. More and more organizations have used information systems to accomplish important works, which makes our work and life convenient. However, there are also many problems, especially the information security. Therefore, not only the managers, but also the users of the information systems are paying more attention to the information security. The firewall is more and more important role in information security.This thesis explains the process of using Visual Basic development tool to design the firewall. It begins with the research situation of content filtering firewall to analyze technical feasibility and economic viability combining the existing software and hardware situation. It introduces the key technology used in design and related concept of firewall and propose the requirement details and overall design. Finally, according to the thoughts of introducing models one by one, it explains the designs of models such as IP address filtering, port filtering, data packet filtering and security log. The test shows that this system has realized the basic functions defined by requirements and operates well.