Powerful DDoS Attack Defense Solution for Stable Network Services

1. Attacking Bandwidth
   Network congestion and response delays usually occur when the number of packets reaches or exceeds the upper limit of the network capacity. Distributed denial - of - service (DDoS) attacks take advantage of this by sending massive packets to a target, occupying all of its bandwidth and causing legitimate requests to go unanswered, thus achieving denial of service. This attack, while simple, is limited in its effectiveness because it relies on the network performance of the host under the attacker's control, and the source of the attack can be easily traced. For this reason, attackers have developed the strategy of reflection attacks. In this strategy, the attacker sends special packets with forged target IP addresses to third - party servers (i.e., reflectors), causing these servers to be spoofed into sending response data to the target address, which not only consumes the target's bandwidth resources, but also makes it difficult to track down the real attacker.
2. Attacking TCP Connection
   When the attacking system establishes a TCP connection, a three - time handshaking process is required between the client and the server. The information about this process is recorded in a so - called connection table. However, the capacity of this table is limited, and after reaching the upper limit, the server will not be able to process new TCP connection requests. An attacker quickly fills the server's connection table by controlling multiple hosts to initiate a large number of malicious TCP connection requests, in particular by sending a large number of TCP SYN (synchronization) messages. These messages cause the server to allocate resources for each request to wait for the connection to complete, thus rapidly exhausting the connection table, and as a result making it impossible for new connection requests from legitimate users to be accepted. This strategy effectively prevents the target server from establishing a new TCP connection with a legitimate client, thus achieving denial of service.
3. Attacking Applications
   DNS and Web services are often the main targets of DDoS attacks, especially resource exhaustion attacks, due to their widespread use and central position. With the rapid progress of Web technology, attackers send a large number of malicious HTTP requests to Web servers by controlling numerous hosts, and these requests occupy all the processing power of the server. As a result, normal Web access requests from legitimate users cannot be responded to, making the service unavailable. This kind of attack not only exhausts the server resources, but also may have a significant impact on the business that relies on the operation of the Web service, with a wide range of impacts and serious damages.
4. Hybrid Attacks
   In real - world attack scenarios, attackers usually do not cherry - pick specific attack methods, and their main goal is to achieve their attack objectives by any feasible means. This means that attackers tend to utilize all available resources and tactics to launch a full - scale attack against a target. For defenders, this situation means having to prepare for DDoS attacks from different protocols and different resources, which undoubtedly increases the cost and complexity of analyzing, responding to, and handling attacks. In recent years, as botnets tend to miniaturize, attackers have begun to use small - traffic, slow - attack strategies against the application layer in order to reduce costs, effectively hide the source of the attack, bypass security measures, and at the same time ensure the effectiveness of the attack. This strategy, although seemingly trivial, has become increasingly popular and dangerous because it is difficult to be detected by traditional security devices.

DDoS defense

1. Choose high - performance network equipment:
   Make sure that the equipment in your network, such as routers, switches, and hardware firewalls, are high - performance and reputable brands. If possible, establish a special partnership with your network provider so that in the event of an attack, they can restrict traffic at the entrance to the network and effectively defend against certain types of DDoS attacks.
2. Ensure adequate network bandwidth:
   Network bandwidth is a direct factor in the ability to resist DDoS attacks. If the network bandwidth is too low (e.g., only 10M), it will be difficult to resist attacks such as SYN Flood. It is recommended to use at least 100M of shared bandwidth and connect to a 1000M backbone network.
3. Continuously upgrade hardware:
   It is critical to upgrade hardware configurations while ensuring sufficient network bandwidth is available to help effectively combat tens of thousands of SYN attack packets per second. It is also advisable to optimize resource usage to enhance the processing power of the web server.
4. Abnormal Traffic Cleaning:
   Utilize advanced techniques of DDoS hardware firewalls, such as packet rule filtering, data stream fingerprinting detection and packet content customization filtering, to accurately identify and remove abnormal traffic.
5. Staticize web content:
   Staticize web content as much as possible, which not only improves attack resistance, but also makes it more difficult for hackers to invade. For scripts that require access to databases, avoid using proxy access as most traffic using proxy access is likely to be malicious.
6. Distributed Cluster Defense:
   By configuring multiple IP addresses on each node server and ensuring that each node can withstand at least 10G of DDoS attacks. If a node is unable to serve due to an attack, the system automatically switches to another node and returns the attack packet to the sender, which not only ensures the continuity of service, but also protects the network security of the enterprise at a deeper level.