What security feature allows a private IP address to access the Internet by translating it to a public address?

What security feature allows a private IP address to access the Internet by translating it to a public address?
A . NAT
B . hairpinning
C . Trusted Network Detection
D . Certification Authority

View Answer

Answer: A

Explanation:

Now the router itself does not have a problem with IP connectivity to the Internet because the router has a globally reachable IP address (34.0.0.3) in this example. The users are not so fortunate, however, because they are using private IP address space, and that kind of address is not allowed directly on the Internet by the service providers. So, if the users want to access a server on the Internet, they forward their packets to the default gateway, which in this case is R1, and if configured to do so, R1 modifies the IP headers in those packets and swaps out the original source IP addresses with either its own global address or a global address from a pool of global addresses (which R1 is responsible for managing, meaning that if a packet was destined to one of those addresses, the routing to those addresses on the Internet would forward the packets back to R1). These are global addresses assigned by the service provider for R1’s use.

Source: Cisco Official Certification Guide, NAT Is About Hiding or Changing the Truth About Source Addresses,