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From Justin Pasher <>
Subject Re: [users@httpd] Connection flood: how to protect?
Date Mon, 13 Apr 2009 20:46:39 GMT
Kanstantin Reznichak wrote:
> Hello,
> One of my servers was affected by TCP flood attack targeted to http 
> service (Apache 2.2.8). Short attack description: an attacker opens 
> large amount of TCP connections to Apache service and sends few bytes 
> (for example, a single “GET / HTTP/1.1” line) to every opened 
> connection. The HTTP service opens a new process for every such 
> connection and waits for further input. After a short time, HTTPd runs 
> out of connection limit and stops responding.
> Some of my servers are protected by state tracking firewall that 
> protects them against such kind of attack.
> My question: is there possible to configure Apache HTTPd in order to 
> protect it against these attacks?

Check out mod_limitipconn. You can restrict the number of simultaneous 
connections from individual IP addresses.

Justin Pasher

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