From owner-freebsd-hackers Mon Oct 22 12:21:28 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from silby.com (cb34181-a.mdsn1.wi.home.com [24.14.173.39]) by hub.freebsd.org (Postfix) with ESMTP id 1605537B405 for ; Mon, 22 Oct 2001 12:21:19 -0700 (PDT) Received: (qmail 70233 invoked by uid 1000); 22 Oct 2001 19:21:16 -0000 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 22 Oct 2001 19:21:16 -0000 Date: Mon, 22 Oct 2001 14:21:16 -0500 (CDT) From: Mike Silbersack To: Terry Lambert Cc: David Malone , Zhihui Zhang , Subject: Re: Limiting closed port RST response In-Reply-To: <3BCED5E7.3FAE9EB8@mindspring.com> Message-ID: <20011022141612.B70111-100000@achilles.silby.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Thu, 18 Oct 2001, Terry Lambert wrote: > The problem is what to do when you are attacked. > > You need to balance resiliance in the face of attack with the > ability to bear a legitimately high load. > > -- Terry I understand that, and can understand leaving rate limiting off on the clients so as to produce a realistic picture of how most hosts will react. What I'm not clear on is how the built-in rate limiting hurts a server under either normal conditions or while being attacked. The packets being limited are all error responses of one type or another; dropping them should not hurt clients connecting to running services. I've heard the argument that RSTs are important so that old connections are terminated when a server restarts, but I generally reject that argument based on the observation that a downed server probably takes more time to reboot than connections take to time out on their own. The one case I haven't considered much is how load-balancers react to systems behind them not returning RSTs in response to incoming packets; if this is the case you're talking about, I'd like to hear more of what happens and how we can accomidate for it better. Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message