From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?G=E1sp=E1r_Lajos?= Subject: Re: redundancy with Adsl modem Date: Fri, 06 Jan 2012 18:12:03 +0100 Message-ID: <4F072B63.7060609@freemail.hu> References: <1325574854.2270.130.camel@andybev-desktop> <4F041738.9090908@freemail.hu> <4F0493D5.3040001@freemail.hu> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: netfilter-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: =?ISO-8859-1?Q?Usu=E1rio_do_Sistema?= Cc: Lloyd Standish , Andrew Beverley , Mail List - Netfilter Hi, > yes, I need redundancy. when an line adsl come down all traffic go to > other line adsl. I couldn't have done this on linux machine. if you > has any how to about please post here. How do you want to do that??? If you have two connections then you have two external IP-s... If one goes down then you can not simply use the other one... Just think about these steps: In normal connection: 1. a local host (A - 192.168.1.1) sends a packet from LAN to an external host (C - 8.8.8.8) 2. the firewall applies source NAT to the packet and sends it out as if it were coming from the firewall's first external IP (B1 - 1.1.1.1) 3. C sends back a reply to B1 4. B1 forwards it with destination NAT to A. 5. go to step 1. or close the connection If the line goes down between step 2 and step 3 then the reply packet will never get back to B1 and A (because the line is down) !!! If the line goes down after step 4 then you can send it out on the second extrenal IP (B2 - 2.2.2.2) but C will see it as a NEW connection !!! So I think that your request is impossible on IP level. However you can use a proxy or a mail server, etc. etc. etc. Swifty