CCNA: Cisco Certified Network Associate — Question 588

A network engineer must migrate a router loopback interface to the IPv6 address space. If the current IPv4 address of the interface is 10.54.73.1/32, and the engineer configures IPv6 address 0:0:0:0:0:ffff:a36:4901, which prefix length must be used?

Answer options

• A. /64
• B. /96
• C. /124
• D. /128

Correct answer: D

Explanation

The correct prefix length for a loopback interface in IPv6 is /128, which indicates a single unique address. Other options like /64 and /96 are typically used for subnets or larger address ranges, while /124 is not standard for loopback interfaces.