What if we do not define outside interface in NAT configuration?

johnifanx98

Say, a typical NAT configuration, that has "ip nat inside source" and inside interface defined. The translation and the reverse translation are done at the inside interface. Routing outward/inward are done by the routes. It seems to me in this case, everything should function even we skip defining the outside interface.

Legacy User

Try it in a lab and do a debug ip packet to see how it flows. Try it with and without the ip nat outside command on the outside interface check the result.

Host-> inside interface | router | outside interface -> Internet router,
Ping from the host to the internet router and document what you see when you try it.