I have a Cisco ASA 5510 running 9.1(4), presently i have a static nat port forwarding all inbound TCP 25 traffic to an internal email scanner's IP address. This is all working fine.
What i would like to know is whether it is possible to setup the ASA NAT config in such a way that if the email scanner failed the ASA would would then NAT all inbound TCP 25 traffic to another specified internal device.
I had in mined something like setting up sla monitoring to the email scanner from the ASA and if it failed to responed having a backup or lower priority NAT kickin.
I have found examples of using this method with outbound dynamic natting to two different ISP's but have had no luck finding any examples of a solution similar to what i would like to achieve.