Why was the RFC 1918 address space defined? (CCNA 200-301)

Correct answer: A. conserve public IPv4 addressing.
RFC 1918 defined the private IP address spaces (10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16) to help conserve the limited public IPv4 address space.

The key reasons for defining the RFC 1918 private address space were:
- Public IPv4 addresses were becoming scarce, so private addresses could be used within internal networks without consuming public addresses.
- Many organizations did not need globally unique IP addresses for their internal networks, so private addresses could be used without causing conflicts.
- The use of Network Address Translation (NAT) allowed private addresses to be translated to public addresses when communicating with the internet, further conserving public IPv4 space.

The other options are not the primary reasons for defining the RFC 1918 address space:
B. While NAT does use the RFC 1918 addresses, NAT was not the primary driver for defining the private address space.
C. The RFC 1918 addresses are for IPv4, not IPv6, so they do not directly preserve IPv6 address space.
D. Reducing overlapping IP addresses was a secondary benefit, not the main purpose for defining the private address space.