From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willy Tarreau Subject: Re: tcp_tw_recycle broken? Date: Sat, 15 Nov 2008 16:52:28 +0100 Message-ID: <20081115155228.GZ24654@1wt.eu> References: <20081115055748.GY24654@1wt.eu> <874p2916hb.fsf@basil.nowhere.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Karl Pickett Return-path: Received: from 1wt.eu ([62.212.114.60]:1245 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345AbYKOPwd (ORCPT ); Sat, 15 Nov 2008 10:52:33 -0500 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Sat, Nov 15, 2008 at 10:47:10AM -0500, Karl Pickett wrote: > On Sat, Nov 15, 2008 at 8:09 AM, Andi Kleen wrote: > > "Karl Pickett" writes: > >> > >> May I just confirm.. is tcp_tw_reuse NOT dependent on receiving timestamps? > > > > The big problem is that both are incompatible with NAT. So if you > > ever talk to any NATed clients don't use it. > > > > -Andi > > > > -- > > ak@linux.intel.com > > > > > Hmph. Running the test again - after getting a little sleep - > timestamps do indeed determine if tw_reuse/recyle work. I must not > have let all the tw buckets expire before changing my timestamp > settings last night. > > Since > A. I don't want to rely on arbitrary web servers having timestamps > B. People say it breaks NAT for clients, and the settings are global only, > > I will just set TCP_TIMEWAIT_LEN to 10 seconds and call it a day. you should increase it a bit. I've encountered occasional issues at 15s, but none at 20s. > Sure would be nice if it was a tunable, so only the most heavily > loaded customers could set it... Indeed. other OSes (eg Solaris) ship with standard values and let us adjust them. Willy