Can the destination address be changed by using outside NAT?

Routing protocols cannot be changed.

Here is my network:

Network Diagram

  • Can you confirm where you are performing NAT and why? If you are tracking CRI_1 with icmp echo for example then just use a route-map to set your next-hop ip address based on the behaviour of the track object.
    – MattE
    Jan 19, 2014 at 8:15
  • 1
    Sorry MattE. I am actually tracking CRI_1 from Host_R1 (not from GW_R1) and I can do changes only on Host_R1. GW_R1 and other routers are out of my control. Hence I thought NAT is the only solution.
    – Mahesh M
    Jan 19, 2014 at 9:11
  • If I change next-hop to and if the packet coming from Host has destination address of, packet will get dropped. What I want is that when IPSLA triggers, the destination IP in the packet coming from Host should change automatically.
    – Mahesh M
    Jan 19, 2014 at 10:01
  • I assume this is related to some form of disaster recovery mechanism. If so, is there only one host at each location, or are we talking about many hosts? Jan 19, 2014 at 14:12
  • Yes. This is for the redundancy mechanism. There is only one host at each location. Also, In the Host, only one IP (of destination server) can be given.
    – Mahesh M
    Jan 20, 2014 at 20:21

1 Answer 1


I'm not sure this will work. I don't have a lab to try it, but it works great on paper ;)

In this example, host will connect to, which is a natted address.

access-list 10 permit
access-list 20 permit

route-map CRI-1 permit 10
match ip address 10

route-map CRI-2 permit 10
match ip address 20

ip nat outside source static route-map CRI-1
ip nat outside source static route-map CRI-2
  • How does this failover to once the connection to fails?
    – Ryan Foley
    Mar 23, 2014 at 13:24
  • This part doesn't. As I recall, the issue was how to do NAT. Using IPSLA to trigger routing was already understood. Feel free to add that part if you like.
    – Ron Trunk
    Mar 23, 2014 at 16:08
  • No need, I was just reading the "Requirement" portion of the network diagram, which doesn't have much to do with the OP.
    – Ryan Foley
    Mar 23, 2014 at 21:22

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.