Solution to the difference between the ip converted by nat and the port ip

When doing NAT, the IP address of NAT’s internal to external transfer is not the same as the IP address of the port. At this time, as long as the router of the next hop in the external network, configure an external network to reach NAT
and then introduce static routing in ospf That's it

ip route 101.0.0.0 255.255.255.240 100.0.0.1

redistribute static subnets