From owner-freebsd-isp Sun Sep 24 22:29:43 2000 Delivered-To: freebsd-isp@freebsd.org Received: from verdi.nethelp.no (verdi.nethelp.no [158.36.41.162]) by hub.freebsd.org (Postfix) with SMTP id 7E2C337B43C for ; Sun, 24 Sep 2000 22:29:40 -0700 (PDT) Received: (qmail 98413 invoked by uid 1001); 25 Sep 2000 05:29:38 +0000 (GMT) To: tom@sdf.com Cc: abcjr@southwind.net, freebsd-isp@FreeBSD.ORG Subject: RE: Using 'private net' IPs for WAN Addresses From: sthaug@nethelp.no In-Reply-To: Your message of "Sun, 24 Sep 2000 21:19:54 -0700 (PDT)" References: X-Mailer: Mew version 1.05+ on Emacs 19.34.2 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Date: Mon, 25 Sep 2000 07:29:38 +0200 Message-ID: <98411.969859778@verdi.nethelp.no> Sender: owner-freebsd-isp@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > > Here is a great description on why one should not use RFC 1918 addresses > > for inter-router links: > > > > http://www.worldgate.com/~marcs/mtu/ > > Wow... MTU path detection. Most routers use the same MTU on all > interfaces, so it isn't a factor. Sorry, that's wrong. There are plenty of routers with 1500 byte Ethernet MTUs, and considerably higher MTUs on serial/ATM/SDH interfaces. > Next, if you assign a /30 for every p2p interface, you can only achieve > 50% utilization of the address space (2 used out of 4). That isn't enough > to meet the threshold to get more address space. I know a a network > provider that is numbering hundreds of p2p links just to free up address > space because they don't meet the density requirements. So you have only 50% utilization of the address space for your p-p links. Unless you are very different from other providers, this is going to be a very small fraction of your total address space. Not using RFC 1918 addresses for p-p links on the Internet is still good advice. Steinar Haug, Nethelp consulting, sthaug@nethelp.no To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message