Hello Chris
If we look at the description of the ip nat inside source command and modify it to conform to the ip nat inside destination command, we can see the following:
ip nat inside destination will:
- translate the destination IP address of packets that travel from inside to outside
- translate the source IP address of packets that travel from outside to inside
This is not the inverse of the source command, but it simply changes the address upon which translation is applied, specifically, the destination and not the source address of the packets.
I hope this has been helpful!
Laz