Received: from localhost (unknown [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 2E91C2E2F76 for ; Fri, 11 Jan 2008 22:56:45 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 98533-10 for ; Fri, 11 Jan 2008 22:56:39 -0400 (AST) Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id 017072E2F65 for ; Fri, 11 Jan 2008 22:56:39 -0400 (AST) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id m0C2uc6G026696 for ; Fri, 11 Jan 2008 21:56:38 -0500 (EST) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id m0C2ucSC026693 for ; Fri, 11 Jan 2008 21:56:38 -0500 (EST) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Fri, 11 Jan 2008 21:56:38 -0500 (EST) From: Greg Smith X-X-Sender: gsmith@westnet.com cc: PostgreSQL Performance Subject: Re: Best way to index IP data? In-Reply-To: <00045B34-A238-46B9-8641-C0A40C5CCCE5@blighty.com> Message-ID: References: <36e682920801101541o7626bbddj428617144240c554@mail.gmail.com> <13179.1200064791@sss.pgh.pa.us> <20080111162747.GT5294@mathom.us> <24044.1200082058@sss.pgh.pa.us> <20080111212703.GU5294@mathom.us> <20080111213710.GD8260@alvh.no-ip.org> <20080111220235.GX5294@mathom.us> <20080111222403.GA7527@crankycanuck.ca> <1259C7B1-C948-4326-B827-849C64B61A16@blighty.com> <20080111230055.GB7618@crankycanuck.ca> <00045B34-A238-46B9-8641-C0A40C5CCCE5@blighty.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200801/100 X-Sequence-Number: 28339 On Fri, 11 Jan 2008, Steve Atkins wrote: > You may well need netmasks to configure your interface, but there's > absolutely no need for them to identify an IP endpoint, which is all you > need to identify the destination the packet is going to, and that is the > most common use of IP addresses. Technically you can't ever send a packet unless you know both the endpoint and your local netmask. As the sender, you're obligated to determine if the destination is on your local LAN (in which case you send it there) or if it goes to the gateway. That's similar to a routing decision, but it's not quite--if you don't have to look in a routing table, it's not actually part of routing. I believe this sort of detail is why subnet masks are considered required for some things even though it doesn't seem like they are needed. Regardless, the details of how the packets move aren't important to some applications, and arguing over what the RFCs do and don't require doesn't change that. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD