Nginx restricts access frequency configuration to prevent malicious attacks

Nginx restricts access frequency configuration to prevent malicious attacks

With the development of the Internet, website security has become an important issue. In order to prevent malicious attacks, we need to limit access frequency. As a high-performance web server, Nginx can achieve this goal through configuration.

Nginx provides a module called limit_req_module, which can limit access frequency. Before configuring, we need to make sure the module is enabled. In the nginx.conf file, we find the http node and add the following code to it:

http {
    ...
    limit_req_zone $binary_remote_addr zone=myzone:10m rate=5r/s;
    ...
}

In the above code, limit_req_zone is used to define a memory area that records the number of visits to each IP address. . $binary_remote_addr is an Nginx variable that represents the client's IP address. zone=myzone is the name of a zone and can be customized. 10m means the area is 10 megabytes in size. rate=5r/s means that up to 5 requests are allowed per second.

Next, we can apply this restriction in the specific location configuration. For example, we want to limit an interface, the code is as follows:

location /api/ {
    ...
    limit_req zone=myzone burst=10 nodelay;
    ...
}

In the above code, the limit_req instruction is used to enable the request frequency limit module and specifies the previously defined zone name myzone. burst=10 means that after exceeding the limit frequency, up to 10 requests will be delayed. Nodelay means that if the frequency limit is exceeded, there will be no delay, but a 503 error will be returned directly.

In addition to the above configuration method, we can also limit the specified time period. For example, we only want to limit it within the working time period, the code is as follows:

location /api/ {
    ...
    limit_req zone=myzone burst=10 nodelay;
    limit_req_status 403;
    limit_req_log_level error;
    limit_req_time 8h;
    ...
}

In the above code, limit_req_time is used to specify the restricted time period, here we limit it to 8 hours. Other instructions such as limit_req_status and limit_req_log_level are used to configure the return status code and logging level when the frequency limit is exceeded.

It should be noted that the above configuration only limits the access frequency of a single interface. If we want to restrict the entire website, we can configure it in the server node. The code is as follows:

server {
    ...
    limit_req zone=myzone burst=10 nodelay;
    ...
}

Through the above configuration, we can effectively limit the impact of malicious attacks on the website. However, it should be noted that the granularity of frequency restrictions should be determined by specific business needs and should not be too strict, otherwise it will affect the access experience of normal users.

To summarize, Nginx’s limit_req_module module can help us limit access frequency to prevent malicious attacks. Through reasonable configuration, the security of the website can be protected and the user's access experience can be improved. I hope this article is helpful to everyone!

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