HTTP Flood & DDoS Filter via Nginx

Try adding something like the following directives to your nginx config to prevent HTTP Flooding & Distributed Denial of Service (DDoS) :

http {
	limit_conn_zone $binary_remote_addr zone=conn_limit_per_ip:10m;
	limit_req_zone $binary_remote_addr zone=req_limit_per_ip:10m rate=5r/s;

	server {
		limit_conn conn_limit_per_ip 10;
		limit_req zone=req_limit_per_ip burst=10 nodelay;
	}
}

See http://nginx.org/en/docs/http/ngx_http_limit_conn_module.html and http://nginx.org/en/docs/http/ngx_http_limit_req_module.html for more info

There's all the following directive http://nginx.org/en/docs/http/ngx_http_core_module.html#limit_rate

NOTE: http://www.botsvsbrowsers.com/details/504401/index.html says the above user agent is not a known bot

Reference:

• StackOverflow.com - Nginx Filter HTTP Flood & DDoS