小肚子灌满了(h)

When a client accesses a server's web service, The client sends a message to the network card, The tcp/ip stack is part of the kernel, Therefore, the client information is transferred to the web service in user space through the kernel's TCP protocol, At this time, the destination destination of the client message is on the socket (IP: Port) that the web service is listening for. When a web service needs to respond to a client request, The destination destination of the response message sent by the web service is the client, At this time, The IP and port that the web service listens on becomes the origin instead, As we said, Netfilter is the real firewall, It is part of the kernel, Therefore, if we want the firewall to achieve the goal of "fire prevention", You need to set up checkpoints in the kernel. All incoming and outgoing messages have to pass through these checkpoints. After checking, those that meet the release conditions can be released, while those that meet the blocking conditions need to be blocked. As a result, input checkpoints and output checkpoints appear. These checkpoints are not called "checkpoints" but "chains" in iptables.杨长帆微微点头：抄家吧，看看咱们会稽首富究竟有多富。黄豆还钓了好几条鲫鱼呢。《笑傲江湖》小说的人气渐渐地又超过了《天河魔剑录》。Use the-S option to indicate the "source address" in the "matching condition", that is, if the source address of the message belongs to the address corresponding to-S, then the message meets the matching condition, and-S means source, indicating the source address.但是悬疑盗墓类小说毕竟是小众中的小众。同学、供餐、社团活动…