Destination Unreachable Message

1

0 - No route to destination

1 - Communication with the destination is administratively prohibited, such as a firewall filter

2 - Not assigned

3 - Address unreachable

4 - Port unreachable

A Destination Unreachable message (Type 1) is generated in response to a packet that can not be delivered to its destination address for reasons other than congestion. The reasons for the non-delivery of a packet is described by code field value.

Packet Too Big Message

2

0

A Packet Too Big message is sent in response to a packet that it cannot forward because the packet is larger than the Maximum Transmission Unit (MTU) of the outgoing link.

Time Exceeded Message

3

0 - Hop limit exceeded in transit

1 - Fragment reassembly time exceeded

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 an initial hop limit value that is too small.

Parameter Problem Message

4

0 - Erroneous header field encountered

1 - Unrecognized next header type encountered

2 - Unrecognized IPv6 option encountered

A Parameter Problem message is generated in response to an IPv6 packet with problem in its IPv6 header, or extension headers, such the node cannot process the packet and must discard it.

Echo Request Message

128

0

Used to check and troubleshoot connectivity using the IPv6 ping command.

Echo Reply Message

129

0

This message is generated in response to an echo request message.