Re: SYN Flooding

From: Ben Okopnik (fuzzybear@pocketmail.com)
Date: 08/13/01


Date: Sun, 12 Aug 2001 23:17:20 -0400
From: Ben Okopnik <fuzzybear@pocketmail.com>
To: focus-linux@securityfocus.com
Subject: Re: SYN Flooding
Message-ID: <20010812231719.B950@pocketmail.com>

On Thu, Aug 09, 2001 at 11:28:13AM -0700, Mark O'Brien wrote:
>
> If your Linux Kernel supports it you can turn on TCP Syncookies like this:
>
> # Like floodguard on a PIX
> echo -n "Enabling TCP Syncookies (floodguard)..."
> echo 1 >/proc/sys/net/ipv4/tcp_syncookies
> echo "done."
>
> I do this in my firewall startup scripts.

Do realize, however, that your kernel has to be compiled with
"CONFIG_SYN_COOKIES" turned on; it's off by default.

Ben Okopnik
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