Cisco CCNA (200-301)Network FundamentalsHard
An IPv6-enabled host sends a packet to the address `ff02::1`. What is the purpose of this destination address?
- ATo resolve a hostname to an IPv6 address.
- BTo send a packet to all IPv6 devices on the local link.
- CTo establish a point-to-point connection with a router.
- DTo communicate with a specific, globally routable server.
Show answer & explanationAnswer & explanation
Correct answer: B. To send a packet to all IPv6 devices on the local link.
The IPv6 address `ff02::1` is the all-nodes link-local multicast address. When a packet is sent to this address, it is received by all IPv6-enabled devices on the same local network segment (link). This address is commonly used by Neighbor Discovery Protocol (NDP) for tasks like host discovery and duplicate address detection.
Why the other options are wrong
- A. DNS is used to resolve hostnames to IP addresses, not sending packets to `ff02::1`.
- C. Point-to-point communication uses unicast addresses, not multicast addresses like `ff02::1`.
- D. Global Unicast Addresses are used for specific, globally routable communication, not `ff02::1`.
IPv6 All-Nodes Multicast Address
The IPv6 `ff02::1` address is a link-local multicast address that targets all IPv6-enabled devices on the same local network segment, used for local discovery and communication.
- Prefix `ff02::/16` indicates link-local multicast.
- `ff02::1` is the 'all-nodes' address.
- Used by Neighbor Discovery Protocol (NDP) for various functions.
Memory trick: FF02::1: 'All-Nodes' on 'One' link, shouting out to everyone!