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Which Internet control message protocol (ICMPv6) message type would you receive if you do not have the permiss

Which Internet control message protocol (ICMPv6) message type would you receive if you do not
have the permission to remotely access a remote computer?

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A.
Packet Too Big.

B.
Time Exceeded.

C.
Redirect.

D.
Destination Unreachable.

Explanation:
A Destination Unreachable message SHOULD be generated by a router, or by the IPv6 layer in
the originating node, in response to a packet that cannot be delivered to its destination address for
reasons other than congestion. (An ICMPv6 message MUST NOT be generated if a packet is
dropped due to congestion.)
If the reason for the failure to deliver is lack of a matching entry in the forwarding node’s routing
table, the Code field is set to 0 (NOTE: this error can occur only in nodes that do not hold a
“default route” in their routing tables).
If the reason for the failure to deliver is administrative prohibition, e.g., a “firewall filter”, the Code
field is set to 1.
If there is any other reason for the failure to deliver, e.g., inability to resolve the IPv6 destination
address into a corresponding link address, or a link-specific problem of some sort, then the Code
field is set to 3.
A destination node SHOULD send a Destination Unreachable message with
Code 4 in response to a packet for which the transport protocol (e.g., UDP) has no listener, if that
transport protocol has no alternative means to inform the sender. (Reference: RFC 2463)
Incorrect Answers:
A: A Packet Too Big MUST be sent by a router in response to a packet that it cannot forward
because the packet is larger than the MTU of the outgoing link. The information in this message is
used as part of the Path MTU Discovery process [PMTU].Sending a Packet Too Big Message
makes an exception to one of the rules of when to send an ICMPv6 error message, in that unlike
other messages, it is sent in response to a packet received with an IPv6 multicast destination
address, or a link-layer multicast or link-layer broadcast address. (Reference: RFC 2463)
B: If a router receives a packet with a Hop Limit of zero, or a router decrements a packet’s Hop
Limit to zero, it MUST discard the packet and send an ICMPv6 Time Exceeded message with

Code 0 to the source of the packet. This indicates either a routing loop or too small an initial Hop
Limit value. (Reference: RFC 2463)
C: Neighbor Discovery defines five different ICMP packet types: A pair of Router Solicitation and
Router Advertisement messages, a pair of Neighbor Solicitation and Neighbor Advertisements
messages, and a Redirect Message. The Redirect is used by routers to inform hosts of a better
first hop for a destination. )Reference: RFC 2461)


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