From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Lloyd Standish" Subject: Re: redundancy with Adsl modem Date: Fri, 06 Jan 2012 12:16:39 -0600 Message-ID: References: <1325574854.2270.130.camel@andybev-desktop> <4F041738.9090908@freemail.hu> <4F0493D5.3040001@freemail.hu> <4F072B63.7060609@freemail.hu> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4F072B63.7060609@freemail.hu> Sender: netfilter-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="iso-8859-1"; format="flowed delsp=yes" To: =?iso-8859-1?Q?Usu=E1rio_do_Sistema?= , =?iso-8859-1?Q?G=E1sp=E1r_Lajos?= Cc: Andrew Beverley , Mail List - Netfilter On Fri, 06 Jan 2012 11:12:03 -0600, G=E1sp=E1r Lajos wrote: > 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 se= cond 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. I think any sort of "uplink redundancy" such as "Usuario de Sistema" is= looking for must be on the connection level, unless one is connecting = to a server using some sort of link bonding or multilink protocol, whic= h has to be supported on the gateway computer. I have never done that. My suggestions to Usuario for uplink redundancy assume that if an inter= face/uplink goes down, the connection *will* be broken, but any followi= ng connections will avoid the failed interface/uplink. I think that is= the best that can usually be done to provide Internet connection redun= dancy. In my scenario, load-balancing is also performed by selecting t= he interface for NEW connection from the LAN to Internet at random. --=20 Lloyd