Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 27 Jul 2001 11:19:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 27 Jul 2001 11:19:08 -0400 Received: from minus.inr.ac.ru ([193.233.7.97]:47373 "HELO ms2.inr.ac.ru") by vger.kernel.org with SMTP id ; Fri, 27 Jul 2001 11:18:48 -0400 Message-Id: <200107270032.EAA00456@mops.inr.ac.ru> Subject: Re: Subtleties of the 0.0.0.0 netmask (inet_ifa_match) To: pflau@us.ibm.COM (Allen Lau) Date: Fri, 27 Jul 2001 04:32:00 +0400 (MSD) Cc: linux-kernel@vger.kernel.org In-Reply-To: from "Allen Lau" at Jul 26, 1 06:15:01 am From: Alexey Kuznetsov X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Original-Recipient: rfc822;linux-kernel-outgoing Hello! > o Does addresses with 0.0.0.0 netmask have scope RT_SCOPE_NOWHERE? Why? > o and does it imply that routing would never route to them? Even if you set this, it does not imply anything, but that address will not be used on any packet while automaitc source address selection. > o Are there subtle differences between 0.0.0.0 and 255.255.255.255 netmasks? Subtle? :-) They are on exactly opposite poles. > The inet_ifa_match function seems to be wrong with 0.0.0.0 netmask. ... > The 0.0.0.0 netmask matches everything! Of course. Zero mask matches everything. > Will there be any routing problems if we use the 0.0.0.0 netmask? No problems provided you wanted this. F.e. default route is route with netmask zero, it matches all, so that all the addresses are routed there. It is exactly which happens in your setup, but all the addresses fall to loopback. Looking at your original purpose, you wanted mask 255.255.255.255. Alexey - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/