In Cisco NAT terminology, which address type represents the inside host address after translation, as it appears on the external or public network?

Introduction / Context:
Cisco NAT terminology distinguishes several different views of addresses involved in translation. Understanding these terms is important for interpreting show commands and troubleshooting NAT behaviour. The inside and outside qualifiers describe whether an address belongs to the internal or external side of the network, while local and global describe whether the address is seen from the internal perspective or represents the address as seen in the global Internet.

Given Data / Assumptions:

An inside host has a private address that is translated by NAT.

The question asks specifically about the inside host address after translation, that is, the address others on the external network will see.

Cisco uses the four key labels inside local, inside global, outside local and outside global.

Only one of these corresponds to the post translation address of the inside host.

Concept / Approach:
Inside local is the address assigned to an inside host before translation, often a private RFC 1918 address such as 192.168.1.10. Inside global is the address that the same inside host appears to have on the external network after translation, usually a public or routable address. Outside global is the real address of an outside host on the Internet, while outside local is how that outside host might be represented inside the local network in some NAT scenarios. For this question, we want the translated address of the inside host as seen externally, which is inside global.

Step-by-Step Solution:
Visualise a simple NAT example: an inside host 192.168.1.10 connects to the Internet through a router that maps it to 203.0.113.5. From the inside network perspective, 192.168.1.10 is the inside local address. This is the address configured on the host itself. The router translates this to 203.0.113.5 when sending packets out to the Internet. This public address is the inside global address, representing the inside host in the global address space. The outside web server might have an address such as 198.51.100.20. That address is the outside global address since it is the real address of the external host. Any special representation of that external address inside the local network would be referred to as an outside local address if such a mapping existed, which is not the case in this simple example.

Verification / Alternative check:
If you run show ip nat translations on a Cisco device, you will see a table with columns labelled inside local, inside global, outside local and outside global. Entries typically show something like 192.168.1.10 mapped to 203.0.113.5, confirming that 192.168.1.10 is inside local and 203.0.113.5 is inside global. This reinforces the definition that the inside host address after translation is the inside global.

Why Other Options Are Wrong:
Option a, inside local, is the inside host address before translation, usually private and not routable on the public Internet.

Common Pitfalls:
Option b, outside local, refers to how an external host might be represented inside the local network in advanced NAT scenarios; it does not describe the inside host after translation.
Option d, outside global, is the genuine address of an outside host in the global Internet, not of the inside host.
Option e, public outside, is not standard Cisco terminology and should not be used when discussing NAT types in exam contexts.

Common Pitfalls:
Students often confuse local and global, assuming that local always means private and global always means public. In reality, these terms describe perspective: local is how the address appears from inside the network, and global is how it appears from outside. Similarly, inside and outside refer to which side of the NAT boundary the host lives on. Keeping these two axes clear will make NAT troubleshooting much easier.

Final Answer:
The inside host address after translation, as seen on the external network, is called the inside global address.