netdev - Re: [PATCH v2 net-next 11/11] tcp: rate limit ACK sent by SYN

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Message-ID: <CADVnQy=bR=zWiDwyrzjaJ9qHSeJJ7mAUvoxgQ57AgG-VK5wtaw@mail.gmail.com>
Date:	Fri, 1 Apr 2016 12:05:20 -0400
From:	Neal Cardwell <ncardwell@...gle.com>
To:	Eric Dumazet <edumazet@...gle.com>
Cc:	"David S . Miller" <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>,
	Eric Dumazet <eric.dumazet@...il.com>,
	Tom Herbert <tom@...bertland.com>,
	Willem de Bruijn <willemb@...gle.com>,
	Maciej Żenczykowski <maze@...gle.com>
Subject: Re: [PATCH v2 net-next 11/11] tcp: rate limit ACK sent by SYN_RECV
 request sockets

On Fri, Apr 1, 2016 at 11:52 AM, Eric Dumazet <edumazet@...gle.com> wrote:
> Attackers like to use SYNFLOOD targeting one 5-tuple, as they
> hit a single RX queue (and cpu) on the victim.
>
> If they use random sequence numbers in their SYN, we detect
> they do not match the expected window and send back an ACK.
>
> This patch adds a rate limitation, so that the effect of such
> attacks is limited to ingress only.
>
> We roughly double our ability to absorb such attacks.

Thanks, Eric!

Acked-by: Neal Cardwell <ncardwell@...gle.com>

neal