From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andre =?iso-8859-1?q?Guimar=E3es?= Subject: Re: NAT addresses - RFC or tradition? Date: Tue, 22 May 2007 16:46:25 -0300 Message-ID: <200705221646.25925.ramoni@databras.com.br> References: <001c01c79ca7$0c1717e0$5a05a8c0@nisgaa.net> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <001c01c79ca7$0c1717e0$5a05a8c0@nisgaa.net> Content-Disposition: inline List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-bounces@lists.netfilter.org Errors-To: netfilter-bounces@lists.netfilter.org Content-Type: text/plain; charset="iso-8859-1" To: netfilter@lists.netfilter.org It's quite simple. You're using public IPs in your internal networks. Some of these IPs may exist and have an owner an maybe even a web site. You'll be in trouble in the day you wish to acess one of these IPs on the=20 internet because you won't reach them because you have them on your network= =20 and so won't route the packets to the internet. The IP's in fact, don't have any thing different, so you can use them and=20 iptables will not have any problems. It's just a route problem, that as you= =20 chose to use these IP's, you won't be able to reach these real public IP's = in=20 the internet. Sorry for the bad english. On Tuesday 22 May 2007 16:26, Paul Blond=E9 wrote: > I've noticed that a lot of people use the 192.168.X.X subnet for internal > networks, is this (and the less-used 10-series) a requirement of some RFC, > or a recommendation that has become tradition? > > We are using a completely different subnet, something similar to (for > example) 42.127.129.X to further obfuscate the internal network from > outside. This, and many other examples, produces a class-A subnet mask > (some produce a class-B) when entered in WinXP's TCP/IP dialog, although > the actual mask we use with it is class-C. > > Is this a no-no? Will it break our server's IPTables when communicating > with it? Am I in for a lot of trouble? The addresses don't seem to cause > any problems, but I don't want this to jump up and bite us in the bottom > sometime down the road. > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Paul Blond=E9 =2D-=20 Andr=E9 Guimar=E3es Databras Inform=E1tica Matriz RJ - 55 (21) 2518-2363 =46ilial ES - 55 (27) 3233-0098 http://www.databras.com.br