Lets say I have a router with two interfaces. The first interface has address 10.1.1.1 and the second interface has address 220.127.116.11
What I want to do is NAT traffic arriving on a particular port on one interface, to an address/port on the other side of the router.
If someone connects to 10.1.1.1:5000 I want to NAT them to 18.104.22.168:4000. The connection being instigated from the network on the 10.1.1.1 side. So in this instance, the destination IP address is NATted, and the source IP address is left intact.
What I am looking for is the static NAT command I need in IOS, and where I should put the "nat inside" and "nat outside" interface commands. No other nat is required on the router.