ICMPv6 Error messages
ICMPv6 error messages are used to report errors happened while IPv6 packet transmission in forwarding or delivery. ICMPv6 error messages are normally sent by a destination node computer-like device or a router.
The left-most bit (high order bit) of the 8-bit Type field of an ICMPv6 Error Message is reserved as 0. So, the value of the Type field in an ICMPv6 Error Message can be between 0 to 127.
Click the following link to learn more about binary, decimal and hexadecimal numbers.
Following paragraph is copied from RFC 792
ICMPv6 messages are grouped into two classes: error messages and informational messages. Error messages are identified as such by a zero in the high-order bit of their message Type field values. Thus, error messages have message types from 0 to 127; informational messages have message types from 128 to 255.
Below image shows the minimum and maximum possible values for Type field in an ICMPv6 Error message. Please refer below image.
Type and Code values for ICMPv6 Error messages
Following table lists important Type and Code values for ICMPv6 Error Messages. Please note that the Type field value for ICMPv6 error messages are between 0 and 127.
| Type Field in ICMPv6 Message | Code Field in ICMPv6 Message | Description |
|---|---|---|
| Destination Unreachable (Value 1) | 0 | No Route to destination network |
| 1 | Administratively prohibited | |
| 2 | Beyond scope of source address | |
| 3 | IPv6 address unreachable | |
| 4 | Port unreachable | |
| 5 | Source address failed | |
| 6 | Reject route to destination | |
| 7 | Error in Source Routing Header | |
| Packet Too Big (Value 2) | 0 | Packet too big for next hop link |
| Time Exceeded (Value 3) | 0 | Hop Limit exceeded |
| 1 | Fragment reassembly time exceeded | |
| Parameter Problem (Value 4) | 0 | Header field error |
| 1 | Unrecognized Next Header type | |
| 2 | Unrecognized IPv6 option | |
| Private experimentation (100) | Private experimentation. Not for general use. | |
| Private experimentation (101) | Private experimentation. Not for general use. | |
| Reserved (127) | Reserved for future expansion |
ICMPv6 Error Message wireshark capture
Following images show the network topology for ICMPv6 Destination not reachable (no route to destination) Error Message Wireshark capture, ICMPv6 Error Message wireshark capture for ICMPv6 Echo Request Message. Please note that the Type value for ICMPv6 Destination not reachable message is 1 and Code value is 0.
Written by Jajish Thomas.
Last updated on 19th May, 2024.