How configure Dual ISP failover

[Arup Dutta]

Hi all,

        i have two isp connection.i want to creat dual ISP failover between them...i am sending sho run text....it was not working .please please help me to solve it.

[Ganesh Hariharan]

Hi all,
        i have two isp connection.i want to creat dual ISP failover between them...i am sending sho run text....it was not working .please please help me to solve it.

Arup,

Check out the below link discussion hope to help

https://supportforums.cisco.com/thread/2002420?tstart=30

If helpful do rate the valauble post

Ganesh.H

[Arup Dutta]

hi Ganesh

thank you for your replying but please make sure that it will

working because today i will implement according to your suggestion.thank

you again.

On Fri, Jan 29, 2010 at 5:37 PM, ganeshh.iyer <

[Ganesh Hariharan]

hi Ganesh
               thank you for your replying but please make sure that it will
working because today i will implement according to your suggestion.thank
you again.
On Fri, Jan 29, 2010 at 5:37 PM, ganeshh.iyer <

Arup,

As per the link and failover mechanism provided in the link you are going to proceed with your setup then i belive your setup is somewhat same as discussed in those previous thread.

It will be better if you can share your complete setup diagram because in your previous thread a genral query reagarding dual link failover that whay i refer the previous discussion.

Hope to help

Ganesh.H

[Arup Dutta]

Hi Ganesh,

1>i have one 1841 router and three fast Ethernet port.

2>and two isp connection one is fa0/1(rilance 512 kb) another one is

fa0/0(vsnl 2mb)

3>router is connected to firewall and NAT is working by firewall

4>now i want when VSNL is goes down with out interrupt my network shift

automatic to Rilance.

5>i can't use BGP

please help me.

On Sat, Jan 30, 2010 at 11:03 AM, ganeshh.iyer <

[Ganesh Hariharan]

Arup,

If you cannot use bgp then you can achive by static routing with IP SLA configuration in router to achive the same,check out the below sample configuration hope that helps.

Configure two default routes in router towards both the isp's.

Configure IP SLA track in router.Check out the below sample config for IP SLA which will help out to track the link status and when ever there is link problem as per the track configuration the default route will removed from cisco router routing table and the traffic will moving to next available ISP.

Check out the below sample config on IP SLA with some explanation:-

ip sla 1
icmp-echo 192.168.1.2
timeout 500
frequency 1
ip sla schedule 1 life forever start-time now

ip sla 2
icmp-echo 172.16.1.2
timeout 500
frequency 1
ip sla schedule 2 life forever start-time now

IP sla 1 will sends icp echo to ISP 1 ip address every 1 second and IP sla 2 will send it to ISP 2

track 10 rtr 1 reachability
delay down 1 up 1
!

track 20 rtr 2 reachability
delay down 1 up 1
!

if ip sla 1 did not get icmp replay within 1 second track 10 will be considered as down ( from ISP 1) track 20 same for ISP 2

ip route 0.0.0.0 0.0.0.0 192.168.1.2 track 10
ip route 0.0.0.0 0.0.0.0 172.16.1.2 track 20

we have two default routes each one point to one of the ISP's IP address, also each staticdefault route is associated with the corresponding IP SLA track created above in this case if ISP 1 link is down the first default route will disappear from the routing table.

Hope that help

If helpful do rate the valauble post

Ganesh.H

[Arup Dutta]

hi Ganash,

i am sending possible fail over config which i am going to

implement.

plz verify it.if have any missing please mention it into text file.

On Sat, Jan 30, 2010 at 11:58 AM, ganeshh.iyer <

[Ganesh Hariharan]

hi Ganash,
                i am sending possible fail over config  which i am going to
implement.
plz verify it.if have any missing please mention it into text file.
On Sat, Jan 30, 2010 at 11:58 AM, ganeshh.iyer <

    
        

        Attachments:
        
po 30-01-2010.TXT.zip (703 bytes)
        

Arup,

Configuration seems to be ok it should work in your setup.after configuraing check out the below command for verifiication

#sh track

#sh ip sla mon operational-state

it will tell you the current status of the track and sla monitoring status in router.

Hope to help

All the best

Ganesh.H

[Arup Dutta]

Hi Ganash,

i am grateful for your replying but still my router not

working.actually my network like that

1>router Fa0/0 is connected to MUX Ethernet port by CAT5 cable for ISP1

2>router Fa0/1 is connected directly to ISP2

3>now problem is when i unplug CAt5 cable manually between MUX and router

then it goes switch over to another ISP

but when fiber link (connected to MUX )is goes down then it not switch

over.

please i wait for your valuable remark

On Sat, Jan 30, 2010 at 12:53 PM, ganeshh.iyer <

[Ganesh Hariharan]

Hi Ganash,
                i am grateful for your replying but still my router not
working.actually my network like that
1>router Fa0/0 is connected to MUX Ethernet port by CAT5 cable for ISP1
2>router Fa0/1 is connected directly to ISP2
3>now problem is when i unplug CAt5 cable manually between MUX and router
then it goes switch over to another ISP
    but when fiber link (connected to MUX )is goes down then it not switch
over.
please i wait for your valuable remark
On Sat, Jan 30, 2010 at 12:53 PM, ganeshh.iyer <

Arup,

Fiber connectivity is between where from MUX to ISP1, If yes then you should have configured ip sla track for isp1 interface ip address if it goes down then automatic switch over will do as per the configuration.

HTH

Ganesh.H

[Arup Dutta]

Hi,

how i configure ip sla track for isp1 interface .please give me one

example.

i am waiting your valuable response .

On Mon, Feb 1, 2010 at 10:46 AM, ganeshh.iyer <

[Ganesh Hariharan]

Hi,
  how i configure ip sla track for isp1 interface .please give me one
example.
i am waiting your valuable response .
On Mon, Feb 1, 2010 at 10:46 AM, ganeshh.iyer <

Arup,

I have already given a sample configuration in previous thread anyway check out the below sample configuration

ip sla 1
icmp-echo 192.168.1.2  --- ISP1 peer end router ip
timeout 500
frequency 1
ip sla schedule 1 life forever start-time now

track 10 rtr 1 reachability
delay down 1 up 1

ip route 0.0.0.0 0.0.0.0 192.168.1.2 track 10

Hope that clear out your query !!

Ganesh.H

[kaushal.pawan]

You can check on 

http://www.unixhowto.in/2017/02/27/nat-failover-with-dual-isp-on-cisco-router-configuration-explained-with-example/

[Marwan ALshawi]

try one of the doucments bellow and you will get what you're looking for

https://supportforums.cisco.com/docs/DOC-8313

https://supportforums.cisco.com/docs/DOC-8353

good luck

if helpful Rate

[rnealy]

This worked great for me, thanks for the post and the examples, greatly appreciated.