300-320 Question #413: Real Exam Question with Answer & Explanation

The correct answer is A: IPV6. In a dual-stack environment where both IPv4 and IPv6 are configured and available, IPv6 is preferred by default. This behavior is defined by RFC 6724 (Default Address Selection for Internet Protocol Version 6), which establishes address selection rules that rank IPv6 addresses ab

Question

Which Dual stack preferred protocol when configured?

Options

AIPV6
BIPV4
CIPX

Explanation

In a dual-stack environment where both IPv4 and IPv6 are configured and available, IPv6 is preferred by default. This behavior is defined by RFC 6724 (Default Address Selection for Internet Protocol Version 6), which establishes address selection rules that rank IPv6 addresses above IPv4 addresses when both are available for a destination. Modern operating systems (Windows, Linux, macOS) and network devices follow these RFC guidelines, preferring IPv6 connections when both protocol stacks are functional. This preference is also reflected in the 'Happy Eyeballs' algorithm (RFC 8305) used in application-layer implementations, which attempts IPv6 first and falls back to IPv4 only if IPv6 fails. IPX (C) is a legacy Novell protocol unrelated to the IP dual-stack discussion.

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