五月综合高清综合网

WOMAN2006The disadvantage of state mode is that many state classes will be defined in the system. Writing 20 state classes is a boring job, and many objects will be added to the system. In addition, because the logic is scattered in the state class, although unpopular conditional branch statements are avoided, it also causes the problem of logic dispersion, and the logic of the entire state machine cannot be seen in one place.……老杨愁到了骨子里，跟这帮家伙有什么好结交的，就算是七品知县，也比这五品千户不知道高到哪里去了。If an attacker sends SYN packets quickly with their own undisguised IP address, this is a so-called direct attack. This attack is very easy to implement because it does not involve spoofing or modifying packets below the user layer of the attacker's operating system. For example, he can simply send many TCP connection requests to implement this attack. However, for this attack to work, the attacker must also prevent his system from responding to SYN-ACK packets because of any ACK, RST, or ICMP (Internet? Control? Message? Protocol) will cause the server to skip the SYN-RECEIVED state (go to the next state) and remove the TCB (because the connection has been successfully established or recycled). Attackers can do this by setting firewall rules, causing the firewall to block all packets (except SYN) to reach the server, or causing the firewall to block all incoming packets so that SYN-ACK packets are discarded before reaching the local TCP handler.