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Poor Mans Backup

Hello,

First of all dont try and compare what ISPs will do for you where ever you come from with Spain. We basically have one ISP and working with them is a nightmare in plain terms. If you can actually get a techie who understands what you want your in luck, but he=B4ll always end up saying:

"But you cant do that!"=B4

So basically unless you want the ISPs $$$$$$ solution you are totally on your own. And companies here are all about the cheap solution.

Here=B4s the setup:

Two business class ADSL lines (8MG each) coming into a Cisco 1721 with two ADSL WICs. One of the ADSL lines is in use (line_prod). The other line (line_back) does nothing. Each line has two public IPs we get to use. One for the router and another for the PIX 515 that sits behind the router. The networks for each line are completely different.

Line_prod goes down about once a year. It usually only goes down for a few hours but once it went down for two days. The slick looking bosses whose fat wallets denied me Frame Relay with SLAs peek into the data center and ask why mail isnt working. You know what I=B4d like to say but since unemployment in my area runs at about 25% I have to shut up.

So what kind of options do I have to set up some kind of semi-automatic failover? Some manual intervention will need to happen since I have only one Ethernet interface on the Router. Also the Ethernet interface on the PIX will need to be changed to the same subnet as the Router...

Any ideas are well appreciated,

Tina

Reply to
Tirenque
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OK there is a solution.

LAN ---- PIX----(DSL A block)----RTR === top dsl a bottom dsl b

On the pix you configure it for the lan block of lan a and your 1721 has int atm0 (routes dsl A ) and atm1 (routes dsl b on a different block)

DSL a block is 65.1.1.1/29 for instance DSL b block is 165.1.1.1/29 for instance

Normal routing out pix into 1721 then out its default gateway of atm0 then you add a weighted gateway of say 20 out atm1

so when atm0 is down it will route out the pix into the router and then to the internet out atm1. All is good except dsl a block won't route out the other provider link so you configure nat on the router for a 1 to 1 conversion mapping dsl a to dsl b and apply out on atm1 and in on fast 0 .

since no nat is configured on atm 0 when the primary is up then then rtr nat won't take place when atm 0 is down then rtr nat will kick in and reroute the traffic to atm1

Also weighted gateways may not be your best option as many cases your atm interface won't actually go down when you lose internet connectivity so you can track ip addresses on the internet with the following config setup.

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Bob Watson National Data Operations AT&T Advanced Solutions

Reply to
stl-eng

Bob,

You are way ahead of me...is there anyway I could get a look at this configuration? I am a little lost with the concepts and some of the English you use. I dont understand part about mapping DSL A to B.

Thank you for your answer,

Tina

Reply to
Tirenque

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Bob, that surely will work but I think for this case full-feature policy-based routing isn't really necessary, somewhat more simple setup with "conditional" static routing will do just fine. Though I will agree these things are basically the same.

Tina, have a look at

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There is an example of the setup.

Regards, iLya

Reply to
Charlie Root

OK. I will have a look at this doc. Is there a way I could send you a drawing of what I have and what I am trying to do?

Reply to
Tirenque

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