Can private addresses be routed on the Internet without NAT?

• A. No; private addresses are not routable on the public Internet and NAT is typically required.
• B. Yes; private addresses are routable on the public Internet if you have a direct connection.
• C. Only some private ranges are routable on the Internet without NAT.
• D. They can be routed if the ISP approves the route.

Answer: (A)

Private IPv4 addresses are reserved for use inside private networks and are not globally unique on the public Internet. Routers on the Internet do not have routes to these private address blocks, so packets with private addresses cannot be delivered end-to-end across the public Internet. To access Internet hosts, devices inside a private network typically use a Network Address Translation (NAT) device at the network edge. NAT translates the private addresses to a public address, allowing communication with the wider Internet, and then maps the replies back to the correct private host.

So the statement that private addresses are not routable on the public Internet and NAT is typically required is the correct one. The other ideas imply direct routing of private ranges or dependence on an ISP’s approval, which doesn’t align with how Internet routing works for private address blocks.