Hello Maodo
The command ping 19.168.12.3 repeat 1 is used to test if a NAT translation without a default route will function correctly.
The command ping 192.168.23.1 repeat 1 is a completely different test. which is testing the NAT translation between 192.168.23.1 and 192.168.12.1. This can be seen from the words: “Let’s try something else…” before the command as seen below:
Secondly:
There is no difference in the debug output for when the ping goes from R3 to R1. The difference is on the return of the ping. On the return of the ping, with no add-route command, there is no indication of a NAT translation, whereas with the add-route command, the translation occurs correctly.
With these two commands, we are implementing the TWO NAT translations that were implemented in the first section. These are two separate NAT translations creating two separate NVIs.
Yes you are correct, this should read interface range GigabitEthernet 0/1 - 2 I will inform @ReneMolenaar
With the NVI, this problem will have been solved. You can lab it up, test it out and let us know your results!
I hope this has been helpful!
Laz