NAT Support for Cisco FMC Firepower
7000 & 8000 Series Are Not Supported
Current NAT implementation for Firepower appliances supports only Threat Defense NAT policies.
Firepower NAT policies for 7000 & 8000 Series are not supported due to lack of API endpoints
PAT Port Allocation
When Firepower PAT performs a port translation, it tries to use the same port number as the real source. However, if the real port is already in use, it selects a mapped port from the same range as the real port. The ranges are:
IP Fabric’s end-to-end path lookup does not follow this behavior. It can use any port from the matching range for simulation purposes.