Which type of Network Address Translation has a one-to-one mapping between internal and external addresses?

Static NAT is characterized by a one-to-one mapping between internal and external IP addresses. In this configuration, each private IP address on a local network is consistently mapped to a specific public IP address. This allows for a consistent routing path without the need for additional configurations when internal devices need to communicate with external networks.

Static NAT is particularly useful for devices that need to be accessed consistently from the outside, like web servers or email servers, because it ensures that the same public IP address is always linked to a specific internal IP address. This consistent mapping helps in firewall configurations, ease of access for remote users, and maintaining persistent connections with external services.

On the other hand, dynamic NAT involves a pool of public IP addresses to be used on a temporary basis by internal devices, meaning the mapping is not fixed and can change. Port Address Translation, also known as NAT overload, allows multiple devices to share a single public IP address by using different port numbers. Load balancers distribute network traffic across multiple servers or resources but do not map internal and external addresses. Hence, the clarity of Static NAT's one-to-one mapping sets it apart as the correct answer in this scenario.