Retain existing NAT session with destination NAT

You can use fully qualified domain name (FQDN)-based destination NAT to retain existing NAT sessions even when the DNS resolved IP address changes for the destination NAT pool. To retain the existing NAT session, enable the session-retain at the [security nat destination pool pool-name ] hierarchy level. The NAT and configured policy FQDNs use a single cache. The use of the single cache helps avoid packet drops if you've configured the same FQDN in the policy and NAT.