Cisco Certified Network Associate (CCNA) 2026 – 400 Free Practice Questions to Pass the Exam

The correct answer is indeed the address that is specifically designated for loopback testing, which in this case is "::1". This address is a special address in the IPv6 protocol that defines the loopback interface. The loopback address is used to test the network stack of a device without the need to send any packets on the network. It allows for local communication within the device itself, which is crucial for troubleshooting and testing.

The loopback address in IPv6 serves the same purpose as the 127.0.0.1 address in IPv4, allowing developers and system administrators to verify correct operations of network applications locally. By sending packets to this address, responses can be received from the local machine, confirming that the TCP/IP stack is functioning as expected.

Other addresses mentioned do not serve the loopback purpose. "::0" is typically used to denote the unspecified address and is not meant for any specific loopback function. The address "2000::1" is a global unicast address which is routable on the IPv6 internet, and "FF01::1" represents a multicast address intended for local nodes, thus not applicable for loopback testing.