CCNA: Cisco Certified Network Associate — Question 1336

How is RFC 1918 addressing used in a network?

Answer options

• A. They are used to access the Internet from the internal network without conversion.
• B. They are used in place of public addresses for Increased security.
• C. They are used with NAT to preserve public IPv4 addresses.
• D. They are used by Internet Service Providers to route over the Internet.

Correct answer: C

Explanation

The correct answer is C because RFC 1918 addresses are private IP addresses that are not routable on the Internet and are commonly used with NAT (Network Address Translation) to enable multiple devices on a local network to share a single public IPv4 address. Option A is incorrect as RFC 1918 addresses do not allow direct Internet access without conversion. Option B is misleading because while they do enhance security by keeping internal addresses hidden, their primary purpose is not security. Option D is incorrect because RFC 1918 addresses cannot be used for routing over the Internet.