From mboxrd@z Thu Jan 1 00:00:00 1970 From: Antony Stone Subject: Re: Checksumming Issues Date: Fri, 21 Nov 2003 21:13:44 +0000 Sender: netfilter-admin@lists.netfilter.org Message-ID: <200311212113.hALLDlj29642@agate.rockstone.co.uk> References: Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Errors-To: netfilter-admin@lists.netfilter.org List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" To: netfilter@lists.netfilter.org On Friday 21 November 2003 9:00 pm, Hildebrand, Brian wrote: > www.netfor2.com/tcpsum.htm > > That is the first website I found. I'm sure if you look some more you could > probably find about 500 more. If you do not follow those instructions, you > will get bad checksum returns. Just because it is an OSI layer higher does > not mean it can't include data from lower down the chain. You are right. The TCP checksum contains a "notional IP header" which is included in the calculation. Today is not a good day for me :( It must be somebody else's birthday. Antony. -- I love deadlines. I love the whooshing noise they make as they go by. - Douglas Noel Adams Please reply to the list; please don't CC me.