Backup route to internet using ISDN and Dialer Watch

Unanswered Question
Feb 21st, 2010

Hi All

I am trying to set up a failover backup route to the internet. At the moment all trafic bound for the internet moves through my cisco 2610 router ( and routed via a default route, gateway last resourt to my ISP router internal address (over which I have no control) and then on to the internet.

My Cisco 2610 ( has an ISDN interface that connects to another ISP via Dial-up.

I have set up dialer watch on the 2610 watching 2 IP's on the web and (is there a better IP to watch?), My problem is that when the ADSL goes down. The dialer watch dials the ISDN dialup, BUT due to the default route, traffic still tries to get through to the ADSL router. How do i set thios up, should I use something else rather then dialerwatch. My config is attached.

Many thanks

I have this problem too.
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KARUPPUCHAMY MA... Sun, 02/21/2010 - 23:57


You can use the track based routing. that is configure ip sla and keep ping your primary link ip address if it is not reachable then the route will be automatically removed from your routing table.then all the traffic wil go via your ISDN link,

step by step config

1.configure ip sla to find the reachablity of your gateway

2.configure tracking (track 1 rtr 1 reachability)

3.add this tracking into your ip route statement (ip route your primary gateway track 1)

Thanks & Regards


Giuseppe Larosa Mon, 02/22/2010 - 00:09

Hello Troy,

dialer watch should be used to monitor IP routes not web sites/IP addresses

Dialer watch looks for the presence of the IP routes in the IP routing table.


for monitoring the reachability of an IP address over the internet to decide when the primary route should be considered down you should use reliable static routes.

the primary route state is linked to the result of an IP SLA or other test and it is removed if the test fails.

dialer watch would be a good tool if:

multiple routers are involved

a dynamic routing protocol is used between the routers

monitored routes are learned via the dynamic routing protocol.

Hope to help


troyrowlands Mon, 02/22/2010 - 03:14

Thanks for the help, but is this feature available for my IOS 12.3(18). I tried to following the method suggested i.e. :

but the below step could not be performed:

Step 10

track object-number rtr rtr-operation {state | reachability}


Router(config)# track 123 rtr 1 reachability

Any ideas?



troyrowlands Mon, 02/22/2010 - 06:00

It looks like my IOS does not support SLA, I am still needing some sort of solution to this and have attached my running config. Please help if you have a suggestion. Would I be able to upgrade my IOS to support SLA? My router is a 2610.



KARUPPUCHAMY MA... Mon, 02/22/2010 - 06:16


your current IOS is not supporting ip need to upgrade the IOS to your router.

before that check the RAM capacity of your router and upgrade to the latest stable IOS.It should be above 12.2.

Cisco IOS IP SLAs Hardware Support

• Linksys (IP SLAs Responder only)

• Cisco 800, 1700,1800, 2600,2800, 3500, 3750, 3600,3700, 3800, 6500, 7200, 7500, 7600, 10000, and 12000 Series Routers. Future support includes CRS-1, ONS ML Card, and Cisco 7970 IP phones in 2005

so no probs... you can upgrade your IOS.



troyrowlands Mon, 02/22/2010 - 07:07

Forgive my ignorance, but my IOS version is IOS (tm) C2600 Software (C2600-BIN-M), Version 12.3(18), RELEASE SOFTWARE (fc3)

is this not newer then 12.2?



KARUPPUCHAMY MA... Mon, 02/22/2010 - 07:19


Thanks for your info..but the issue is you running with  (C2600-BIN-M) IOS.This will not support IP SLA.

You need to have adv-ipservices or adv-enterprise ios in your router.

example : c2600-adventerprisek9-mz.124-15.T11.bin ,c2600-advipservicesk9-mz.124-15.T11.bin



Giuseppe Larosa Mon, 02/22/2010 - 07:19

Hello Troy,

it may be a question of feature set.

IOS comes in different feature sets with different capabilities


sh ver | inc image

so we can see what you have on your router.

Hope to help


troyrowlands Tue, 02/23/2010 - 00:48

My IOS image is:

System image file is "flash:c2600-bin-mz.123-18.bin"

I don't have access to any other IOS as this is for a lab. So if there is any way of achieving what I need to do with my current IOS, i would be grateful.




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