Seamless failover for incoming NATs

[Mokhalil82]

Hi Guys  (Diagram Attached)

I have 2 sites Primary and Secondary. I have an internal IPSLA failover setup incase my primary outgoing link fails, all outgoing traffic goes via the secondary site. The issue i have is my incoming NATs. 

So the ISP is using HSRP on their routers so their Virtual IP stays as .17 during a failover, but I am not using HSRP so my external IP changes from .3 to .4 when a failover occurs as it fails over to the secondary router. 

In the event of a failover, my outgoing traffic is fine as I use IPSLA internally but my incoming NATS fail as currently I have not setup Natting on my Secondary router.

How can I do a setup so that my incoming NATS carry on working via both my primary and secondary router?

Will using HSRP on my routers so that my external IP does not change during a failover solve this problem?

Also in regards to doing some dynamic routing with the ISP if this is a solution, how will this work?

Thanks

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

Maybe: http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-software-releases-12-2-t/prod_white_paper0900aecd8052870b.html