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Frank Vilea
Asked: 2011-10-28 04:41:58 +0800 CST

nginx: Prevent DoS by limiting worker processes/connections

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If I limit my nginx worker processes to 1 and allow for 500 connections, what happens if I exceed this limit? Does the server return a 503 Service Unavailable?

Basically, I'm trying to secure my system against DoS and do not expect more than 500 simultaneous connections per second.

nginx denial-of-service

1 Answers

  1. Best Answer

    How many cores your server has ? If you have two cores, i suggest you can set 2 workers and 250 conn. max.

    max_clients = worker_processes * worker_connections

    And Yes, the 501 connection will receive an error. But be carefull, a browser opens 2 connections by default.

    EDIT: One more thing, you can set a max connection limit by IP (10 here) with

    ## Max conns for one ip
 limit_zone gulag $binary_remote_addr 5m;
 limit_conn gulag 10;

    in /etc/nginx/nginx.conf

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