How to change the limits in the Nginx configuration…

Limits in Nginx can be changed by editing configuration files. Main types of limits:

Connection limits: worker_connections
Timeout limits: client_body_timeout, client_header_timeout, send_timeout
Request body size limits: client_max_body_size
Speed limits: limit_rate, limit_conn, limit_req

Example of changing worker_connections in the main events block:

// Changes the maximum number of simultaneous connections that an Nginx worker can accept.
// Increases server throughput.
events {
    worker_connections 4096; // For example, up to 4096
}

Example of changing client_max_body_size in the http, server, or location block:

// Changes the maximum allowed size of the client request body,
// specified by the Content-Length header in the request.
// Used to prevent DoS attacks.
http {
    client_max_body_size 50m; // For example, up to 50 megabytes
    // ... other http settings
}

Example of limiting connection speed for a specific location:

// Limits data transfer speed to the client.
// Used to prevent network overload.
location /downloads/ {
    limit_rate 1024k; // Speed limited to 1024 kilobytes per second (1 MB/s)
}

Example of using limit_conn to limit the number of simultaneous connections to the server or virtual host by a key (e.g., IP address):

// Defines a zone to store connection state.
// Zone name is limit_per_ip, size 10 megabytes.
limit_conn_zone $binary_remote_addr zone=limit_per_ip:10m;

server {
    // ... other server settings

    // Limits the number of connections from a single IP address to 5.
    limit_conn limit_per_ip 5;

    location / {
        // ... location settings
    }
}

Example of using limit_req to limit request processing speed by a key (e.g., IP address):

// Defines a zone to store request state.
// Zone name is req_per_ip, size 10 megabytes.
// Limits speed to 5 requests per second.
// burst=10 allows up to 10 "excess" requests.
// nodelay means requests are processed immediately without delay until burst is exhausted.
limit_req_zone $binary_remote_addr zone=req_per_ip:10m rate=5r/s;

server {
    // ... other server settings

    // Applies the limit to the location /.
    limit_req zone=req_per_ip burst=10 nodelay;

    location / {
        // ... location settings
    }
}

Process of changing:

Find the necessary Nginx configuration file (usually /etc/nginx/nginx.conf and files in /etc/nginx/conf.d/ or /etc/nginx/sites-available/).
Edit the relevant parameter in the appropriate block (events, http, server, location).

Check configuration syntax:

// Test configuration syntax
sudo nginx -t

Reload Nginx to apply changes:

// Reload Nginx
sudo systemctl reload nginx

How to change the limits in the Nginx configuration?