How to defend against DDOS? Teach you practical protection skills and methods

at the moment of rapid development of Internet business, the threat of network attacks is becoming increasingly severe. Among them, DDOS attacks have become the "confidant of many enterprises and webmasters" with the characteristics of large traffic, fast outbreak and wide target. Once attacked, the service card is light, and the business is completely paralyzed, causing immeasurable losses. In order to help everyone build a cyber security defense line, this article will dismantle practical defense DDOS skills and methods from the basic configuration, tool application, architecture optimization and other levels, so that you can master the core idea of responding to attacks.

First, the defense of DDOS needs to do a good job of basic configuration optimization

many DDOS attacks are launched using weak links in the system or application, and optimizing the basic configuration is the first barrier to defend against DDOS, which can reduce the attack breakthrough from the source.

1, close unnecessary ports and services

redundant ports and services running on the server can become potential targets for attackers, such as some idle FTP and Telnet ports, which may be used to launch traffic attacks. Administrators should regularly comb the server port usage, close non-business-essential ports and services, and limit the access range of ports with firewall rules, allowing only trusted IP segments to connect to core business ports to reduce the attack surface.

2, set the number of connections and timeout time limit

for TCP connection class DDOS attack, you can limit the number of concurrent connections of a single IP by adjusting system parameters, such as in Nginx or Apache and other Web servers, set the maximum number of connections and connection timeout time of a single IP, when an IP initiates a large number of invalid connections in a short period of time, the server will automatically cut off the connection, to avoid malicious exhaustion of resources, to protect the normal user's access request can be timely response.

two, defense DDOS to make good use of traffic cleaning tools

when the attack traffic breaks through the basic defense line, professional traffic cleaning tools become the core force of defense against DDOS, which can accurately identify and filter malicious traffic.

1, deployment of cloud traffic cleaning service

for small and medium-sized webmasters or enterprises, the cost of self-built traffic cleaning system is too high, and cloud traffic cleaning service is a more cost-effective solution. Such services will first drain all access traffic to cloud cleaning nodes, identify normal traffic and malicious attack traffic through AI algorithms, filter out abnormal data packets of DDOS attacks, and only forward legitimate traffic to the source server, effectively relieving the traffic bearing pressure of the server.

2, use hardware firewall for local cleaning

For large enterprises with high security requirements, hardware firewalls can be deployed to achieve local traffic cleaning. Hardware firewalls have high-performance data packet processing capabilities, which can detect traffic characteristics in real time, such as identifying abnormal data packet sizes, request frequencies, etc., quickly intercept common DDOS attack traffic such as SYN floods and UDP floods, and support custom rules. They can adjust defense strategies according to business characteristics and adapt to complex network environments.

three, defense DDOS upgradable distributed architecture

the carrying capacity of a single server is limited, once it encounters a large traffic DDOS attack is easy to be defeated, upgrading the distributed architecture can improve the overall anti-attack ability and achieve large-scale protection against DDOS.

1, the introduction of CDN distribution of static resources

CDN is the information delivery network, which will cache the static resources of the website such as pictures, videos, CSS files to multiple nodes around the world. When users visit, they will obtain resources from the nearest nodes, which can not only improve the access speed, but also disperse the traffic pressure. When a DDOS attack is launched, the traffic will be dispersed to each CDN node to avoid all concentrating on the source server. At the same time, the CDN node itself has a certain defense DDOS ability, which can filter some malicious traffic at the node level.

2, using load balance decentralized request

deploy load balancing devices or services, distribute user access requests evenly to multiple backend servers, so that each server only handles part of the request and improves the overall business load. In the event of a DDOS attack, load balancing can automatically mask the attacked abnormal server, forward the request to the normal running server, ensure business continuity, and combine the health check mechanism to monitor the server status in real time and adjust the traffic delivery strategy in time.

4, the defense of DDOS needs to establish an emergency response mechanism

even if a full range of protection, can not completely avoid DDOS attacks, the establishment of a sound emergency response mechanism, can quickly stop loss when the attack occurs, reduce business losses.

1, real-time monitoring of network traffic and status

with the help of professional network monitoring tools, real-time monitoring server bandwidth usage, CPU load, the number of connections and other core indicators, set abnormal alarm threshold, when the sudden surge in traffic, CPU occupancy abnormal rise, the system will send alarm information in time, let the administrator first time to find signs of attack, for the defense of DDOS for valuable response time.

2, develop attack emergency response process

develop a standardized emergency response process in advance to clarify the responsibilities of each position when an attack occurs, such as operation and maintenance personnel responsible for switching traffic to backup nodes, security personnel responsible for analyzing attack characteristics and adjusting defense rules, and customer service personnel responsible for synchronizing user announcements. At the same time, regular emergency drills are organized to test the team's response speed and handling capabilities to ensure that when a real DDOS attack occurs, it can be dealt with in an orderly manner.

To sum up, the defense of DDOS is a systematic project, which needs to be promoted from the four levels of basic configuration optimization, traffic cleaning tool application, distributed architecture upgrade and emergency response mechanism. Daily basic protection, with the help of professional tools to strengthen traffic filtering, improve the carrying capacity through architecture upgrade, and cooperate with the perfect emergency process, can effectively resist different types of DDOS attacks, ensure the stable operation of network services, and build a solid security foundation for business development.