How does Nginx server set the upper limit of buffer capacity?

Set the maximum buffer capacity.

This setting can prevent buffer overflow attacks (also the Server module).

client_div_buffer_size 1k; client_header_buffer_size 1k; client_max_div_size 1k; large_client_header_buffers 2 1k;

After setting, no matter how many HTTP requests, the buffer of the server system will not overflow.