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, 6 Sep 2001 10:04:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 6 Sep 2001 10:04:28 -0400 Received: from spike.porcupine.org ([168.100.189.2]:23049 "EHLO spike.porcupine.org") by vger.kernel.org with ESMTP id ; Thu, 6 Sep 2001 10:04:24 -0400 Subject: Re: ioctl SIOCGIFNETMASK: ip alias bug 2.4.9 and 2.2.19 In-Reply-To: <20010906173534.A21874@castle.nmd.msu.ru> "from Andrey Savochkin at Sep 6, 2001 05:35:34 pm" To: Andrey Savochkin Date: Thu, 6 Sep 2001 10:04:44 -0400 (EDT) Cc: Andi Kleen , Matthias Andree , linux-kernel@vger.kernel.org, Wietse Venema X-Time-Zone: USA EST, 6 hours behind central European time X-Mailer: ELM [version 2.4ME+ PL82 (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Message-Id: <20010906140444.75DC1BC06C@spike.porcupine.org> From: wietse@porcupine.org (Wietse Venema) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrey Savochkin: > > Even if it checked the address it would not be unique because you can have multiple > > interfaces with the same addresses but different netmasks. The same IP address with different netmasks on the same hardware interface? The mind boggles. How does one handle broadcasts? > The only one good reason for an SMTP server to bother about IP addresses at > all is a quick check for mail loops, i.e. a check at the moment of opening > TCP connection to send a message whether your peer is yourself. > Bothering about network masks just doesn't have any valid grounds. The issue is not MTA loop detection. Postfix uses the local netmask info to distinguish between local and remote networks. At the discretion of the sysadmin, systems on local subnets can be granted different rights than random systems on the Internet. If Linux insists on breaking SIOCGIFCONF then so be it, even though it works perfectly well on any non-Linux system that I could lay my hands on. Wietse