How do public IP addresses differ from private IP addresses?

Public IP addresses are unique across the Internet, meaning that no two devices can have the same public IP address at the same time on the global Internet. This uniqueness is essential for the proper functioning of the Internet, as it enables devices to be identified, located, and communicated with correctly regardless of their geographical position. When a device accesses the Internet, it is assigned a public IP address by an Internet Service Provider (ISP), which allows other devices on the Internet to send data to it. In contrast, private IP addresses are used within local networks and can be reused across different private networks, leading to their non-unique nature.

The distinction between public and private IP addresses is fundamental in networking. Public IPs are necessary for external communication, while private IPs facilitate communication within a local network, such as within a home, office, or organization, without needing a different address for every single device connected to the private network. The correct understanding of these concepts is crucial for tasks like configuring routers and managing network security.