Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

isp backup for two lan

Hi,

Here's the scenario

- we have 2 ISP

- we have 2 LAN, we need to let one of the lan (192.168.1.X) to go to ISP1

and the other (192.168.2.X) to ISP2

if ISP1 goes down, all lan should go to ISP2

if ISP2 goes down, all lan should go to ISP1

We've used the attached configuration on lab.

We can't reach pcs or router beyond router directly attached to the main router(router where the configuration was applied)

5 REPLIES
Cisco Employee

Re: isp backup for two lan

Hello,

Use Policy based routing and NAT to configure the same.Set both the ISP's address as next hop in the route map and if 1 router is down, it will route all the traffic via other ISP.

NAT:

http://www.cisco.com/warp/public/556/12.html

Policy Based Routing:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/qos_c/qcpart1/qcpolicy.htm

www.cisco.com/warp/public/732/Tech/plicy_wp.htm

HTH,Please rate if it does.

-amit singh

New Member

Re: isp backup for two lan

Hi Amit,

What should be modified on the config i've sent?

We use only one router for connecting 2 lans and 2 ISP.

Nat seems working

ip nat inside source route-map NAT-TEST interface Ethernet0/0 overload

ip nat inside source route-map NAT-TT interface Ethernet1/0 overload

But we have problem on routing using the following config.

route-map NAT-TT permit 1

match ip address 101

set ip next-hop verify-availability ISP_2 1 track 124

set ip next-hop verify-availability ISP_1 2 track 123

New Member

Re: isp backup for two lan

Hi,

Routing works now.

Backup works only after launching "clear ip nat translation *".

What's missing or Is there a way to do this automatically?

New Member

Re: isp backup for two lan

Try setting your NAT translation timeouts. For example, to timeout UDP port 500 after 20 seconds:

ip nat translation port-timeout udp 500 20

New Member

Re: isp backup for two lan

Hi Martian,

We've used EEM and it's working.

We'll test what you've suggested, it seems simpler.

Thanks

110
Views
0
Helpful
5
Replies
CreatePlease to create content