Which statement about private IPv4 addresses and Internet reachability is true?

• A. Private addresses are globally routable on the Internet.
• B. Private addresses can be used on the Internet without translation.
• C. Private addresses are not routable on the Internet; NAT translates them to a public address for external communication.
• D. Private addresses are reserved for APIPA.

Answer: (C)

Private IPv4 addresses are not globally routable on the public Internet. They exist for use inside a private network, and Internet routers won’t forward packets addressed with those private ranges. To reach external sites, a NAT (Network Address Translation) device translates the private address to a public one before the packet leaves the network. This translation allows many internal devices to share one public IP (commonly using port-based translation, or PAT, in homes and small offices). Because of this, private addresses cannot be used on the Internet without translation.

APIPA addresses (169.254.0.0/16) are reserved for link-local use when DHCP fails and are not meant for Internet reachability, which is why the statement that private addresses require translation for external communication remains true.