From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268079AbUHVT20 (ORCPT ); Sun, 22 Aug 2004 15:28:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268078AbUHVT2Z (ORCPT ); Sun, 22 Aug 2004 15:28:25 -0400 Received: from qfep05.superonline.com ([212.252.122.162]:24982 "EHLO qfep05.superonline.com") by vger.kernel.org with ESMTP id S268076AbUHVT2N (ORCPT ); Sun, 22 Aug 2004 15:28:13 -0400 From: "Josan Kadett" To: "'Brad Campbell'" Cc: Subject: RE: Entirely ignoring TCP and UDP checksum in kernel level Date: Sun, 22 Aug 2004 22:28:10 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.5510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1409 In-Reply-To: <41289C0B.7010805@wasp.net.au> Thread-Index: AcSIScfXEOY9i3vERdyWNWPRKXO4cAAPCXWg Message-Id: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I have found the exact reason why NAT does not work; - The patched linux box ignores IP checksum errors - Since now the source address is mofidified without checksumming, NAT also carries that wrong checksum - Other boxes does not ignore the checksum and drop packets I think the solution is here, I have done many different modifications to get the system redirect packets with wrong checksum. Now all to be done, is to correct this checksum by changing some code in ip_input.c so that it recalculates the checksum when the packets seem to arrive from 192.168.1.1. Where in the code then? -----Original Message----- From: Brad Campbell [mailto:brad@wasp.net.au] Sent: Sunday, August 22, 2004 3:14 PM To: Josan Kadett Cc: linux-kernel@vger.kernel.org Subject: Re: Entirely ignoring TCP and UDP checksum in kernel level Are you trying to ping 192.168.77.1 from 192.168.0.30? Can you give me an iptables -L -n -t nat, ifconfig and route -n from the patched box and also route -n and ifconfig from the dummy client at 192.168.0.30 so I can try and get a handle on what you are doing and how it all is supposed to work?