Which statement best defines a public IP address?

Which statement best defines a public IP address?

• A. It can be reached from the Internet and is globally unique across the Internet
• B. It is restricted to internal networks only
• C. It is assigned to private devices by a home router
• D. It changes with every packet

Answer: (A)

Public IP addresses are addresses that can be reached from the Internet and are globally unique across the Internet. They are routable on the public network and are assigned by Internet authorities or ISPs to ensure that every device on the Internet has a unique address, allowing direct communication from any other Internet host (subject to firewalls and access rules). In contrast, private IP addresses are reserved for internal networks and are not reachable directly from the public Internet. They rely on a NAT gateway to reach external networks, which is why home networks use private addresses for devices and have the router translate to a public address for Internet access. Public IPs don’t change with every packet; they may change over time if the ISP assigns dynamic addresses, but they remain fixed for a period until reassigned, not per packet. So the statement that matches public IP addresses describes reachability from the Internet and global uniqueness.

Public IP addresses are addresses that can be reached from the Internet and are globally unique across the Internet. They are routable on the public network and are assigned by Internet authorities or ISPs to ensure that every device on the Internet has a unique address, allowing direct communication from any other Internet host (subject to firewalls and access rules).

In contrast, private IP addresses are reserved for internal networks and are not reachable directly from the public Internet. They rely on a NAT gateway to reach external networks, which is why home networks use private addresses for devices and have the router translate to a public address for Internet access. Public IPs don’t change with every packet; they may change over time if the ISP assigns dynamic addresses, but they remain fixed for a period until reassigned, not per packet.

So the statement that matches public IP addresses describes reachability from the Internet and global uniqueness.