Dst_Unreach_4_Global.seq - check ICMPv6 Destination
Unreachable code 4
Host/Router
When test starts, states of Neighbor Cache Entry for TN's
addresses are reachable.
This test verifies that NUT sends valid ICMPv6 Destination
Unreachable (code 4) in response to a packet which can not
be delivered to destination port.
And this test verifies that the message processing rule ,
If the message is a response to a message sent to one of the
node's unicast addresses, the Source Address of the reply must
be that same address.
TN NUT
---------------------------
1.
=== UDP packet ===>
src address : TN global address
dst address : NUT global address
port : not used in NUT
2.
<< JUDGMENT >>
<=== ICMPv6 Destination Unreachable ===
Code is 4
<< PASS >>
NUT send ICMPv6 Destination Unreachable.
<< FAIL >>
NUT do not send ICMPv6 Destination Unreachable.
RFC2463 3.1 Destination Unreachable Message
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unused |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| As much of invoking packet |
+ as will fit without the ICMPv6 packet +
| exceeding the minimum IPv6 MTU [IPv6] |
IPv6 Fields:
Destination Address
Copied from the Source Address field of the invoking packet.
ICMPv6 Fields:
Type 1
Code 0 - no route to destination
1 - communication with destination
administratively prohibited
2 - (not assigned)
3 - address unreachable
4 - port unreachable
Unused This field is unused for all code values.
It must be initialized to zero by the sender
and ignored by the receiver.
Description
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.
perldoc V6evalTool