Cisco CCNA (200-301)Network FundamentalsEasy
An administrator is assigning internal IP addresses to hosts in a private office network that will never be routed directly on the public internet. Which of the following address ranges is reserved by RFC 1918 for this purpose?
- A192.0.2.0/24
- B169.254.0.0/16
- C10.0.0.0/8
- D100.64.0.0/10
Show answer & explanationAnswer & explanation
Correct answer: C. 10.0.0.0/8
RFC 1918 reserves three private address ranges: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16, none of which are routable on the public internet. 100.64.0.0/10 is Carrier-Grade NAT space, 192.0.2.0/24 is TEST-NET documentation space, and 169.254.0.0/16 is APIPA.
Why the other options are wrong
- A. This is a documentation/example address block (TEST-NET-1).
- B. This is the APIPA range used for automatic link-local addressing.
- D. This range is reserved for carrier-grade NAT (RFC 6598), not RFC 1918.
RFC 1918 Private Addressing
RFC 1918 defines IPv4 address blocks reserved for use inside private networks and not routed on the public internet.
- 10.0.0.0/8
- 172.16.0.0/12
- 192.168.0.0/16
Memory trick: '10, 172(16-31), 192.168' — private house numbers.