Cisco Certified Network Associate (CCNA) Practice Exam 2025 - Free CCNA Practice Questions and Study Guide

To enable IPv6 routing on a router, the command `ipv6 unicast-routing` is utilized. This command activates the routing capability for IPv6 packets, allowing the router to forward IPv6 traffic between interfaces. By default, IPv6 routing is not enabled on a Cisco router; thus, this command is necessary to ensure that the router can participate in IPv6 routing protocols and process IPv6 information effectively.

The option that states 'ipv6 routing' is a common misconception but does not exist as an actual command; it lacks the specific functionality needed for enabling IPv6 routing. Similarly, options that suggest commands like 'enable ipv6 routing' and 'routing ipv6' also do not correspond to valid syntax in Cisco router configurations. They do not fulfill the requirement to properly activate IPv6 routing, which is why they are incorrect.

The clarity in the command `ipv6 unicast-routing` is what sets it apart, as it is both specific and effective in enabling the router for IPv6 traffic management, thus highlighting its importance in the configuration of IPv6 networking.