From mboxrd@z Thu Jan 1 00:00:00 1970 From: Herve Eychenne Subject: Re: (D)NAT with IPv6 (was "nf_conntrack & NAT") Date: Thu, 8 Dec 2005 12:41:20 +0100 Message-ID: <20051208114120.GF5617@eychenne.org> References: <200511231225.jANCPmYd015427@toshiba.co.jp> <20051123132044.GZ3249@eychenne.org> <20051123132419.GJ24091@fi.muni.cz> <20051206154320.GG4038@rama.exocore.com> <20051206173135.GQ5617@eychenne.org> <20051207145438.GA5617@eychenne.org> Reply-To: rv@wallfire.org Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: Harald Welte , netfilter-devel@lists.netfilter.org Return-path: To: Jozsef Kadlecsik Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-devel-bounces@lists.netfilter.org Errors-To: netfilter-devel-bounces@lists.netfilter.org List-Id: netfilter-devel.vger.kernel.org On Wed, Dec 07, 2005 at 04:09:25PM +0100, Jozsef Kadlecsik wrote: > On Wed, 7 Dec 2005, Herve Eychenne wrote: > > I don't want to use DNAT for load balancing. I want to use DNAT (and > > I'm using it just now with IPv4) to redirect traffic destined to a > > certain IP/port to another IP (private or not) in the most transparent > > way. There are plenty of scenari where I'm willing to do that. > > > > For those who need practical examples (others can stop here) that I'm > > regularly facing myself, here it is. > > > > Then MX of domain points on host A, and I want to redirect SMTP traffic > > to host B (also in my network) in the most atomic way. > > DNS propagation can be slow (caching), and user proxying is too slow > > (and not transparent). > > If there are miraculous mecanisms in IPv6 which enable to achieve that > > redirection as atomically and quickly that DNAT, please let me know. > Yes, use as many IP addresses as you want :-): > Host A: > addressA0: maintenance > addressA1: az advertised SMTP server > addressA2: az advertised HTTP server > ... > Host B: > addressB0: maintenance > addressB1: az advertised SMTP server > addressB2: az advertised HTTP server > ... > If you want to "replace" A as SMTP server by server B, just assign > addressA1 to server B. That's it. No NAT required at all and it > is practically atomic. > (Assumed the same network as you wrote.) So each time you add a service on a host, you should assign a new IP to it (and create the respective DNS name for this IP/service couple!), just in case you may have to redirect its traffic one day? (even if temporary) Oh my... If IPv6 (without DNAT) really implies that, I can still live with IPv4 for a (very) long time! Herve -- _ (°= Hervé Eychenne //) v_/_ WallFire project: http://www.wallfire.org/