What is a characteristic of a valid public IPv4 or IPv6 address?

A valid characteristic of a public IPv4 or IPv6 address is that it is required for communication over the internet. Public IP addresses are unique and globally routable, meaning they can be accessed from anywhere on the internet. When a device has a public address, it can communicate with other devices across the internet without the need for a translation mechanism or additional configuration that would be required for private addresses.

Public addresses allow for efficient routing and delivery of data packets between devices on different networks. This is crucial for services like web browsing, email, and any application that relies on connectivity across the internet.

The other options do not accurately describe the fundamental characteristics of a public IP address. For example, while an IP address may be assigned by a local network administrator, this does not define its validity as public. Similarly, while public IP addresses cannot be used for private networks, this distinction speaks to their usage rather than their validity. Lastly, the assertion that public IP addresses are always fixed is misleading, as they can also be dynamically assigned.