How does Duplicate Address Detection (DAD) avoid IP address conflicts on the link?

• A. The host issues a ping to the tentative address.
• B. The host issues a Neighbor Solicitation for its tentative address, and if no Neighbor Advertisement is received, the address is used.
• C. DAD relies on DNS to check the address.
• D. DAD is performed by ARP.

Answer: (B)

Duplicate Address Detection avoids conflicts by using the Neighbor Discovery Protocol to check whether the tentative IPv6 address is already in use on the local link. When a device generates a new address, it sends a Neighbor Solicitation for that address with an unspecified source. If another device already uses that address, it will respond with a Neighbor Advertisement, signaling a conflict. If no such response is received, the address is considered unique and the device can use it. This process relies on NS/NA messages, not on DNS, ARP, or simply pinging, to ensure only one node on the link uses the address.