It's a trivial matter.仆人离开，准备去拿垃圾了。SYN attack is a kind of DOS attack. It takes advantage of TCP protocol defects and consumes CPU and memory resources by sending a large number of semi-connection requests. SYN attacks can not only affect hosts, but also harm network systems such as routers and firewalls. In fact, SYN attacks can be implemented as long as these systems turn on TCP services no matter what systems are targeted. As can be seen from the above figure, the server receives the connection request (syn=j), adds this information to the unconnected queue, and sends the request packet to the client (syn=k, ack=j+1), then enters the SYN_RECV state. When the server does not receive an acknowledgement packet from the client, it retransmits the request packet and does not delete this entry from the non-connection queue until the timeout. With IP spoofing, SYN attacks can achieve good results, Typically, clients forge a large number of non-existent IP addresses in a short period of time, SYN packets are continuously sent to the server, and the server replies to the confirmation packets and waits for the confirmation of the customer. Since the source address does not exist, the server needs to continuously resend until it timeout. These forged SYN packets will occupy the unconnected queue for a long time, normal SYN requests will be discarded, the target system will run slowly, and in serious cases, the network will be blocked or even the system will be paralyzed.1941年底，日军占领香港。为实现文化控制，日军全城搜捕滞港的中方文化名人。在中共主持下，东江游击队队长叶伟强进入戒备森严的香港，单枪匹马营救邹涛、蔡楚生等诸多文化名人，完成这不可能完成的任务。B4 liver function, hepatitis B surface antigen. 决定放弃一切，就在这时，云开客栈一众人忽然死于“天一神水”之下，而神水宫的宫南燕更是一口咬定是楚留香盗取了他们的“天一神水”。Shiyan is located in the hinterland of the 10th Qinba Mountain area. It is the core water source area of the Middle Route of South-to-North Water Transfer Project. It is a well-known automobile industry base in the country. It is the seat of Wudang Mountain, a world cultural heritage and Taoist holy land. It is also one of the main battlefields for poverty alleviation in the Qinba Mountain area. Through participating in the first season of "Charming China City", Shiyan's "Xianshan, Xiushui and Auto City" three city business cards were further disseminated, promoting the docking of industries and projects and expanding the platform for foreign exchange. Shiyan has gained a brand-new understanding of the local area from all over the world. The city's popularity and reputation have been further improved, and the channels for tourism resources to go out are more spacious. Through Charming China City, Shiyan has made more than 30 appearances in more than 10 mainstream media such as CCTV 1 and CCTV 2, with more than 50 million hits and nearly 100 million attention. Shiyan once occupied the top spot in hot searches for a long time and formed a brand influence market value of more than 10 billion yuan. Since July 2017, the number of tourists in Wudang Mountain has increased by 5 percentage points. At present, more than 20 well-known investors at home and abroad have contacted and formally signed contracts with 5 enterprises such as Hua Bin Group. Through this competition, Shiyan's tourism development concept has undergone a great change, establishing a new concept of global tourism, a new thinking of overall tourism marketing in the city, a new strategy of large-scale investment promotion and capital introduction, and a new thinking of tourism resources integration, thus realizing a change to an open "tourism plus" integration development mode.
