What types of firewalls are there, a brief introduction to the firewall

With the rapid development of the Internet, every household now has a computer and is connected to the Internet. When the network brings convenience to us, the drawbacks of the Internet are gradually revealed. Many people will be connected when they are connected. The intentional or unintentional attack causes the data stored on the computer to be stolen or lost by the intruder, so the firewall is particularly important. The following system home introduces the classification of the firewall. Classification of firewalls Packet Filtering Firewall This is the first generation firewall, also known as the network layer firewall. When each packet is transmitted to the source host, it will be filtered at the network layer. For illegal data access, the firewall will choose to block and discard. The connection of the firewall can be through a network card, that is, a network card, the IP address of the internal network, the IP address of the public network, and the two network cards. One network card has the IP address of the private network, and the other network card has the IP address of the external network. . 2. Status/Dynamic Detection Firewall Status/Dynamic Detection Firewall, which tracks network connections and packets through the firewall so that the firewall can use an additional set of criteria to determine whether the packet is allowed or denied. It does this by applying some techniques to the communication using the basic packet filtering firewall. 3. Application Proxy Firewall Application Proxy Firewall, also known as an application layer firewall, works on the application layer of OSI. The application proxy firewall does not actually allow direct communication between the networks it connects to. Instead, it accepts communications from specific user applications on the internal network and then establishes a separate connection to the public network server. The above is the classification of the firewall. I believe that everyone has some understanding of the knowledge of the firewall. Everyone should know more about the computer and network knowledge so that they can solve it when they encounter computer problems in the future. This article comes from [System Home] www.xp85.com