RE: Preveting DDOS Syn floods on HTTP servers

["Aditya, ALD [Aditya Lalit Deshmukh]" <aditya.deshmukh () online gateway technolabs net>]

> I was wondering if it was possible for a HTTP servers to prevent 
> DDOS syn floods, attacks from different IP's, like a attack from 
> a IRC network or something like that.

if you are using linux look into tcp_syncookies, a word of caution : it requires a lot of physical memory and this 
allocated memory is non swappable. increasing the value by a small bit would cause quite a bit of increase in memory 
requirments

but your server would be able to handle syn floods more efficiently.


HTTP server cannot be hardened because syn scans are to be blocked by the os : so harden your OS

-aditya


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