From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 25 Jan 2001 16:03:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 25 Jan 2001 16:03:28 -0500 Received: from pizda.ninka.net ([216.101.162.242]:33930 "EHLO pizda.ninka.net") by vger.kernel.org with ESMTP id ; Thu, 25 Jan 2001 16:03:21 -0500 From: "David S. Miller" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14960.37982.739742.487042@pizda.ninka.net> Date: Thu, 25 Jan 2001 13:02:22 -0800 (PST) To: Alexandre Hautequest Cc: linux-kernel@vger.kernel.org Subject: Re: non-random IP IDs In-Reply-To: <980451650.3a7081428753c@webmail.fesppr.br> In-Reply-To: <980451650.3a7081428753c@webmail.fesppr.br> X-Mailer: VM 6.75 under 21.1 (patch 13) "Crater Lake" XEmacs Lucid Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alexandre Hautequest writes: > I was playing a bit on some of my machines with Nessus (www.nessus.org), and it > told me the following text: > Nessus is saying something bogus to you. > Is there some option to dinamically enable this random IP ID's, or I need to > change something and recompile, or just "No way!"? Ip IDs only matter when packets can be fragmented. If the packet cannot be fragmented, the Ip ID field serves no purpose. Whatever the nessus thing did to test this, it used a IP packet to/from the linux box which had the "Don't Fragment" bit set in the IP header, which as a consequence means the ID field is meaningless. If the "don't fragment" bit were not set, and fragmentation was possible, Linux will use a randomized ID field. The nessus folks need to fix their test. Later, David S. Miller davem@redhat.com - 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/