What is the first step in the NAT configuration process?

Before any NAT translation rules can be applied, the router must be informed which interfaces connect to the private network (inside) and which connect to the public network (outside) using the `ip nat inside` and `ip nat outside` commands on the respective interfaces, establishing the NAT boundaries.

While defining public and private IP addresses is part of NAT, the foundational step is identifying the interfaces that delineate the inside and outside networks.

Defining IP address pools is a step in configuring dynamic NAT or PAT, but it comes after the inside/outside interfaces have been specified.

'Global and local interfaces' are not standard NAT terminology; NAT uses 'inside' and 'outside' interfaces to distinguish private and public sides of the network.