From owner-freebsd-net@FreeBSD.ORG Thu May 24 11:19:59 2012 Return-Path: Delivered-To: net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3E1E61065673 for ; Thu, 24 May 2012 11:19:59 +0000 (UTC) (envelope-from bzeeb-lists@lists.zabbadoz.net) Received: from mx1.sbone.de (mx1.sbone.de [IPv6:2a01:4f8:130:3ffc::401:25]) by mx1.freebsd.org (Postfix) with ESMTP id BD0648FC18 for ; Thu, 24 May 2012 11:19:58 +0000 (UTC) Received: from mail.sbone.de (mail.sbone.de [IPv6:fde9:577b:c1a9:31::2013:587]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mx1.sbone.de (Postfix) with ESMTPS id 8CEBB25D3A00; Thu, 24 May 2012 11:19:57 +0000 (UTC) Received: from content-filter.sbone.de (content-filter.sbone.de [IPv6:fde9:577b:c1a9:31::2013:2742]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.sbone.de (Postfix) with ESMTPS id BA007BE7A09; Thu, 24 May 2012 11:19:56 +0000 (UTC) X-Virus-Scanned: amavisd-new at sbone.de Received: from mail.sbone.de ([IPv6:fde9:577b:c1a9:31::2013:587]) by content-filter.sbone.de (content-filter.sbone.de [fde9:577b:c1a9:31::2013:2742]) (amavisd-new, port 10024) with ESMTP id J259MKgzCEPk; Thu, 24 May 2012 11:19:55 +0000 (UTC) Received: from orange-en1.sbone.de (orange-en1.sbone.de [IPv6:fde9:577b:c1a9:31:cabc:c8ff:fecf:e8e3]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by mail.sbone.de (Postfix) with ESMTPSA id 33C34BE7A07; Thu, 24 May 2012 11:19:55 +0000 (UTC) Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii From: "Bjoern A. Zeeb" In-Reply-To: <20120524.094321.74735847.sthaug@nethelp.no> Date: Thu, 24 May 2012 11:19:54 +0000 Content-Transfer-Encoding: 7bit Message-Id: <98091B3E-B728-483F-99FE-C65BD82CA089@lists.zabbadoz.net> References: <20120524071055.GA50710@onelab2.iet.unipi.it> <20120524.094321.74735847.sthaug@nethelp.no> To: sthaug@nethelp.no X-Mailer: Apple Mail (2.1084) Cc: rizzo@iet.unipi.it, net@freebsd.org Subject: Re: use of non-contiguous masks in address lookups ? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 24 May 2012 11:19:59 -0000 On 24. May 2012, at 07:43 , sthaug@nethelp.no wrote: >> every now and then the issue comes up on whether we still need >> to support non-contiguous masks in address lookups. >> I seem to remember someone (perhaps on this list) making a >> case for their presence, but forgot the details. >> So, does anyone know of a practical use of non contiguous masks ? > > I vote for removing non-contiguous masks. They are incompatible with > CIDR, which was introduced in 1993 (!). > > Non-contiguous masks have been unsupported in many routers produced > the last 10 years or so. Contrary I still know people using them and relying on it. Not sure on which version they are. I am not quite sure what micro-optimizations on legacy IP will help us after a decade or longer. Let it rest and die gracefully the next years. Of course, fixing bugs still considered good:) /bz -- Bjoern A. Zeeb You have to have visions! It does not matter how good you are. It matters what good you do!