防火墙是保护网络安全的主要产品。它的作用是在不安全的网络环境中构造一个相对安全的子网环境,以防止发生不可预测的、潜在破坏性的侵入。它是提供信息安全服务,实现网络和信息安全的基础设施。防火墙可通过监测、限制、更改跨越防火墙的数据流,尽可能地对外部屏蔽网络内部的信息、结构和运行状况,以此来实现网络的安全保护。 Firewall is the main product to protect network security. Its role is to construct a relatively secure subnet in an insecure network environment to prevent unpredictable and potentially damaging intrusion. It is the infrastructure that provides information security services and network and information security. Firewalls can achieve network security by monitoring, limiting, changing the flow of data across firewalls, and shielding external information, structures, and health inside the network as much as possible.