Which ICMP message is used when a destination or intermediate router cannot deliver a packet because the destination is unreachable?
ICMP Destination Unreachable communicates delivery failures such as network, host, or port unreachable conditions.
Which protocol is used by IPv4 hosts to report membership in multicast groups?
IGMP manages IPv4 multicast group membership between hosts and local multicast routers.
Which statement about IPv6 fragmentation is correct?
IPv6 routers do not fragment packets in transit; fragmentation is performed by the source using the Fragment extension header.
Which IPv6 address type is used for one-to-nearest delivery and is assigned to more than one interface?
An IPv6 anycast address identifies a set of interfaces; routing delivers the packet to the nearest member according to routing metrics.
Which IPv6 address scope is intended for communication within a single local link?
IPv6 link-local addresses (fe80::/10) are valid only on the local link.