An administrator configures a web server that must be accessible to anyone outside the office.

A public IP address is required so internet-based clients can route traffic to the organization’s network. Public addresses are globally routable and are normally assigned by an internet service provider. The web server may itself use a private address, but the organization’s internet-facing router must have a public address and use port forwarding or static NAT to direct HTTP or HTTPS requests to the internal server. Merely having an IPv4 or IPv6 address is insufficient because either protocol can use addresses that are not externally routable. A dynamic address can be public, but it may change and is therefore unsuitable for reliable server hosting unless dynamic DNS is configured. The defining requirement is public reachability, not whether the address is IPv4, IPv6, static, or dynamic. Therefore, a public IP address is the best answer.