How to control on the return traffic?

[mohammed hashim]

Hi,

if you have a router connected to two public links, and there are some applications published through link 1, and other applications published through link 2. NAT is used for all application and mapped to different IP.

The router has a default route through both links to access the internet, it might be BGP or static route ,,, etc. 

my question is, if a user from the internet wants to communicate to an application, the router will NAT and route the packet to back-end server, the server will reply, and when the packet reaches the router, it has two possible route to the internet, it might choose the other link which has different public IP.
how we can let it forward this packet through the correct link?

without doing so, the end-user machine will drop the packet because public IP changed.

thanks, 

[balaji.bandi]

Hope below example help you :

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

[paul driver]

Hello

There are multiple ways to perform route path manipulation

One such way with static routing would be Policy Based routing

In this case you would ONLY have one default static not two which would send all non local traffic via that specified next hop and with PBR also active any source traffic matching say within a access-list relating to this policy would be routed via the secondary path