As mentioned previously, the term inside refers to those networks that are owned by an organization and that must be translated. Inside this domain, hosts will have address in the one address space, while on the outside, they will appear to have addresses in a another address space when NAT is configured. The first address space is referred to as the local address space while the second is referred to as the global address space.
Similarly, outside refers to those networks to which the stub network connects, and which are generally not under the organization's control. As will be described later, hosts in outside networks can be subject to translation also, and can, thus , have local and global addresses.
To summarize, NAT uses the following definitions: