From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 17 Jan 2001 13:02:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 17 Jan 2001 13:02:00 -0500 Received: from Cantor.suse.de ([194.112.123.193]:61198 "HELO Cantor.suse.de") by vger.kernel.org with SMTP id ; Wed, 17 Jan 2001 13:01:55 -0500 Date: Wed, 17 Jan 2001 19:01:26 +0100 From: Andi Kleen To: Tony Gale Cc: Andi Kleen , linux-kernel@vger.kernel.org, Jussi Hamalainen Subject: Re: IP defrag (was RE: ipchains blocking port 65535) Message-ID: <20010117190126.B2859@gruyere.muc.suse.de> In-Reply-To: <20010117183547.A2528@gruyere.muc.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from gale@syntax.dera.gov.uk on Wed, Jan 17, 2001 at 05:44:30PM -0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 17, 2001 at 05:44:30PM -0000, Tony Gale wrote: > > On 17-Jan-2001 Andi Kleen wrote: > > > > Connection tracking always defrags as needed. > > masquerading/NAT/iptables > > with connection tracking uses that. > > > > This means that if any of these are enabled and your machine acts > > as a > > router lots of CPU could get burned in defragmentation, and packets > > will not forwarded until all fragments arrived. > > Hmm... ok, what if I'm on a single nic system using ipchains on the > input and want to always defrag before they hit the ipchains > filter, what settings would I need? No masq., no NAT. (bearing in > mind that ipchains differentiates between SYN+frag and noSYN+frag. You probably need to just load ip_conntrack_standalone and make sure it runs. It has a higher priority than ipchains in the prerouting chain and should just defragment things. Better would it be to just write a small netfilter module with a higher priority than ipchains that always defrags. Actually I thought I've once seen such a beast, but it doesn't seem to be included in the main kernel now that I look for it. It's all only a few lines of code anyways. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/