RE: Preveting DDOS Syn floods on HTTP servers

[Fernando Gont <fernando () gont com ar>]

At 16:22 09/03/2004 +0000, MARTIN M. BĂ©noni wrote:

> Well, I do not know IIS, but on Apache tehere are a couple of options 
> which can help preventing from DDOS attacks. Here are a buch of examples:
> -  KeepAlive
> -  MaxKeepAliveRequests
> -  KeepAliveTimeout
> -  ...
>
> I will not say you will or will not, I think you can just HELP PREVENTING!

Why should it help?
TCP's keepalive was meant to clean the system from half open connections.
So it should keick in *fter* a connection has been established, which is 
not the case of a SYN flood or a reflection attack, as the connections 
never get established.

For SYN flood, you should enable syncookies.


--
Fernando Gont
e-mail: fernando () gont com ar || fgont () acm org



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