With the rapid development of network technology, network security has become increasingly serious. In response to this trend, the emergence of a number of network security products, firewalls is one of the earliest and the largest use of network security products. A firewall is the access control between two networks one or a group of software or hardware system, is a very effective network security technology. Firewall divided by technology: "packet filter type" and "application proxy-type" two categories. All Windows-based operating system core technology is the personal firewall network packet filtering technology.
Packet filtering is the process of the communication of data through the analysis of network protocol filtering, to meet the required safety rules in advance of data packets through, so that those who do not meet safety regulations discarded packets.
This article describes the Windows-based design and implementation of packet filtering firewall.
