From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266250AbUHVGQu (ORCPT ); Sun, 22 Aug 2004 02:16:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266252AbUHVGQu (ORCPT ); Sun, 22 Aug 2004 02:16:50 -0400 Received: from wasp.net.au ([203.190.192.17]:31656 "EHLO wasp.net.au") by vger.kernel.org with ESMTP id S266250AbUHVGQt (ORCPT ); Sun, 22 Aug 2004 02:16:49 -0400 Message-ID: <41283A74.101@wasp.net.au> Date: Sun, 22 Aug 2004 10:17:24 +0400 From: Brad Campbell User-Agent: Mozilla Thunderbird 0.7+ (X11/20040730) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Josan Kadett CC: linux-kernel@vger.kernel.org Subject: Re: Entirely ignoring TCP and UDP checksum in kernel level Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Josan Kadett wrote: > That is certainly what I require but I need some guidelines; I investigated > into the issue and fount out that; > > - By only changing the source address coded in the IP header > - And by just applying checksum to IP header [Not TCP or UDP] > > The problem would be gone since when the source IP in the IP address field > is validated, the checksum in the underlying protocol is automatically > validated (because the sender system had already computed this CRC using the > IP address which we want to write onto the packet) > > I do not have much time to build a code just for this purpose and thus I am > looking for a simple app. or some other way... So if we took any packet that came in from 192.168.1.1 and substituted 192.178.77.1 for the Source address and then re-calculated the IP checksum you would be up and running? Regards, Brad