Internet Control Message Protocol version 6 (ICMPv6) Parameters

Note

Code field subregistries that are not explicitly documented by the 
specification defining the associated Type value are not individually 
listed here.  Nevertheless, the meaning of Code field values depend 
upon the Type value [RFC 4443, Section 2.1].  Any specification 
wishing to define a previously unspecified Code subregistry for a 
given Type should note the procedures in [RFC 4443, Section 6.1].

Type 0 - Reserved

Code
No registrations at this time.

Type 1 - Destination Unreachable

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code	Name	Reference
0	no route to destination
1	communication with destination administratively prohibited
2	beyond scope of source address	[RFC4443]
3	address unreachable
4	port unreachable
5	source address failed ingress/egress policy	[RFC4443]
6	reject route to destination	[RFC4443]
7	Error in Source Routing Header	[RFC6550][RFC6554]
8	Headers too long	[RFC8883]

Type 2 - Packet Too Big

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 3 - Time Exceeded

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code	Name
0	hop limit exceeded in transit
1	fragment reassembly time exceeded

Type 4 - Parameter Problem

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code	Name	Reference
0	erroneous header field encountered
1	unrecognized Next Header type encountered
2	unrecognized IPv6 option encountered
3	IPv6 First Fragment has incomplete IPv6 Header Chain	[RFC7112]
4	SR Upper-layer Header Error	[RFC8754]
5	Unrecognized Next Header type encountered by intermediate node	[RFC8883]
6	Extension header too big	[RFC8883]
7	Extension header chain too long	[RFC8883]
8	Too many extension headers	[RFC8883]
9	Too many options in extension header	[RFC8883]
10	Option too big	[RFC8883]

Type 128 - Echo Request

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 129 - Echo Reply

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 130 - Multicast Listener Query

Registration Procedure(s)

Standards Action or IESG Approval

Reference

[RFC2710]

Available Formats

CSV

Code
0

Type 131 - Multicast Listener Report

Registration Procedure(s)

Standards Action or IESG Approval

Reference

[RFC2710]

Available Formats

CSV

Code
0

Type 132 - Multicast Listener Done

Registration Procedure(s)

Standards Action or IESG Approval

Reference

[RFC2710]

Available Formats

CSV

Code
0

Type 133 - Router Solicitation

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 134 - Router Advertisement

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 135 - Neighbor Solicitation

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 136 - Neighbor Advertisement

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 137 - Redirect Message

Registration Procedure(s)

Standards Action or IESG Approval

Reference

Available Formats

CSV

Code
0

Type 138 - Router Renumbering

Registration Procedure(s)

IETF Review

Reference

[RFC2894]

Available Formats

CSV

Code	Name
0	Router Renumbering Command
1	Router Renumbering Result
255	Sequence Number Reset

Type 139 - ICMP Node Information Query

Registration Procedure(s)

Specification Required

Expert(s)

Unassigned

Reference

[RFC4620]

Available Formats

CSV

Code	Name	Reference
0	The Data field contains an IPv6 address which is the Subject of this Query.	[RFC4620]
1	The Data field contains a name which is the Subject of this Query, or is empty, as in the case of a NOOP.	[RFC4620]
2	The Data field contains an IPv4 address which is the Subject of this Query.	[RFC4620]

Type 140 - ICMP Node Information Response

Registration Procedure(s)

Specification Required

Expert(s)

Unassigned

Reference

[RFC4620]

Available Formats

CSV

Code	Name	Reference
0	A successful reply. The Reply Data field may or may not be empty.	[RFC4620]
1	The Responder refuses to supply the answer. The Reply Data field will be empty.	[RFC4620]
2	The Qtype of the Query is unknown to the Responder. The Reply Data field will be empty.	[RFC4620]

Type 141 - Inverse Neighbor Discovery

Registration Procedure(s)

Standards Action

Reference

[RFC3122]

Available Formats

CSV

Code
0

Type 142 - Inverse Neighbor Discovery

Registration Procedure(s)

Standards Action

Reference

[RFC3122]

Available Formats

CSV

Code
0

Type 144 - Home Agent Address Discovery

Registration Procedure(s)

IESG Approval

Reference

Available Formats

CSV

Code
0

Type 145 - Home Agent Address Discovery

Registration Procedure(s)

IESG Approval

Reference

Available Formats

CSV

Code
0

Type 146 - Mobile Prefix Solicitation

Registration Procedure(s)

IESG Approval

Reference

Available Formats

CSV

Code
0

Type 147 - Mobile Prefix Advertisement

Registration Procedure(s)

IESG Approval

Reference

Available Formats

CSV

Code
0

Type 157 - Duplicate Address Request Code Suffix

Registration Procedure(s)

IETF Review or IESG Approval

Reference

Available Formats

CSV

Code Suffix	Meaning	Reference
0	DAR message	[RFC6775]
1	EDAR message with 64-bit ROVR field	[RFC8505]
2	EDAR message with 128-bit ROVR field	[RFC8505]
3	EDAR message with 192-bit ROVR field	[RFC8505]
4	EDAR message with 256-bit ROVR field	[RFC8505]
5-15	Unassigned

Type 158 - Duplicate Address Confirmation Code Suffix

Registration Procedure(s)

IETF Review or IESG Approval

Reference

Available Formats

CSV

Code Suffix	Meaning	Reference
0	DAC message	[RFC6775]
1	EDAC message with 64-bit ROVR field	[RFC8505]
2	EDAC message with 128-bit ROVR field	[RFC8505]
3	EDAC message with 192-bit ROVR field	[RFC8505]
4	EDAC message with 256-bit ROVR field	[RFC8505]
5-15	Unassigned

Type 160 - Extended Echo Request

Registration Procedure(s)

First Come First Served

Reference

[RFC8335]

Available Formats

CSV

Code	Name	Reference
0	No Error	[RFC8335]
1-255	Unassigned

Type 161 - Extended Echo Reply

Registration Procedure(s)

First Come First Served

Reference

[RFC8335]

Available Formats

CSV

Code	Name	Reference
0	No Error	[RFC8335]
1	Malformed Query	[RFC8335]
2	No Such Interface	[RFC8335]
3	No Such Table Entry	[RFC8335]
4	Multiple Interfaces Satisfy Query	[RFC8335]
5-255	Unassigned

FMIPv6 Message Types (Value 154)

Registration Procedure(s)

RFC Required

Reference

[RFC5568]

Available Formats

CSV

Subtype	Description	Reference
0	Reserved	[RFC5568]
1	Reserved	[RFC5568]
2	RtSolPr	[RFC5568]
3	PrRtAdv	[RFC5568]
4	HI - Deprecated (Unavailable for Assignment)	[RFC5568]
5	HAck - Deprecated (Unavailable for Assignment)	[RFC5568]
6-255	Unassigned

IPv6 Neighbor Discovery Option Formats

Registration Procedure(s)

RFC Required

Reference

Note

IETF working groups with working group consensus and area director approval 
can request reclaimable Neighbor Discovery option type assignments from IANA. 
See Section 13 of [RFC4861].

Available Formats

CSV

Type	Description	Reference
1	Source Link-layer Address	[RFC4861]
2	Target Link-layer Address	[RFC4861]
3	Prefix Information	[RFC4861]
4	Redirected Header	[RFC4861]
5	MTU	[RFC4861]
6	NBMA Shortcut Limit Option	[RFC2491]
7	Advertisement Interval Option	[RFC6275]
8	Home Agent Information Option	[RFC6275]
9	Source Address List	[RFC3122]
10	Target Address List	[RFC3122]
11	CGA option	[RFC3971]
12	RSA Signature option	[RFC3971]
13	Timestamp option	[RFC3971]
14	Nonce option	[RFC3971]
15	Trust Anchor option	[RFC3971]
16	Certificate option	[RFC3971]
17	IP Address/Prefix Option	[RFC5568]
18	New Router Prefix Information Option	[RFC4068]
19	Link-layer Address Option	[RFC5568]
20	Neighbor Advertisement Acknowledgment Option	[RFC5568]
21	PvD ID Router Advertisement Option	[RFC8801]
22	Unassigned
23	MAP Option	[RFC4140]
24	Route Information Option	[RFC4191]
25	Recursive DNS Server Option	[RFC5006][RFC8106]
26	RA Flags Extension Option	[RFC5175]
27	Handover Key Request Option	[RFC5269]
28	Handover Key Reply Option	[RFC5269]
29	Handover Assist Information Option	[RFC5271]
30	Mobile Node Identifier Option	[RFC5271]
31	DNS Search List Option	[RFC8106]
32	Proxy Signature (PS)	[RFC6496]
33	Address Registration Option	[RFC6775]
34	6LoWPAN Context Option	[RFC6775]
35	Authoritative Border Router Option	[RFC6775]
36	6LoWPAN Capability Indication Option (6CIO)	[RFC7400]
37	DHCP Captive-Portal	[RFC8910]
38	PREF64 option	[RFC8781]
39	Crypto-ID Parameters Option (CIPO)	[RFC8928]
40	NDP Signature Option (NDPSO)	[RFC8928]
41	Resource Directory Address Option	[RFC9176]
42	Consistent Uptime Option	[RFC-ietf-6lo-multicast-registration-19]
43-137	Unassigned
138	CARD Request option	[RFC4065]
139	CARD Reply option	[RFC4065]
140-143	Unassigned
144	Encrypted DNS Option	[RFC9463]
145-252	Unassigned
253	RFC3692-style Experiment 1 [1]	[RFC4727]
254	RFC3692-style Experiment 2 [1]	[RFC4727]

Trust Anchor option (Type 15) Name Type field

Registration Procedure(s)

Standards Action or IESG Approval

Reference

[RFC3971][RFC6495]

Available Formats

CSV

Value	Description	Reference
0	Reserved	[RFC6495]
1	DER Encoded X.501 Name	[RFC3971]
2	FQDN	[RFC3971]
3	SHA-1 Subject Key Identifier (SKI)	[RFC6495]
4	SHA-224 Subject Key Identifier (SKI)	[RFC6495]
5	SHA-256 Subject Key Identifier (SKI)	[RFC6495]
6	SHA-384 Subject Key Identifier (SKI)	[RFC6495]
7	SHA-512 Subject Key Identifier (SKI)	[RFC6495]
8-252	Unassigned
253-254	Reserved for Experimental Use	[RFC6495]
255	Reserved	[RFC6495]

Certificate option (Type 16) Cert Type field

Registration Procedure(s)

Standards Action

Reference

[RFC3971]

Available Formats

CSV

Value	Description	Reference
0	Reserved
1	X.509v3 Certificate	[RFC3971]
2-255	Unassigned

Option-Code for Handover Assist Information Option (Type 29)

Registration Procedure(s)

Standards Action or IESG Approval

Reference

[RFC5271]

Available Formats

CSV

Value	Description	Reference
0	Reserved	[RFC5271]
1	AN ID	[RFC5271]
2	Sector ID	[RFC5271]
3-255	Unassigned

Option-Code for Mobile Node Identifier Option (Type 30)

Registration Procedure(s)

Standards Action or IESG Approval

Reference

[RFC5271]

Available Formats

CSV

Value	Description	Reference
0	Reserved	[RFC5271]
1	NAI	[RFC5271]
2	IMSI	[RFC5271]
3-255	Unassigned

Qtypes

Registration Procedure(s)

IETF Review

Reference

[RFC4620]

Available Formats

CSV

Value	Description	Reference
0	NOOP	[RFC4620]
1	Unused	[RFC4620]
2	Node Name	[RFC4620]
3	Node Addresses	[RFC4620]
4	IPv4 Addresses	[RFC4620]
5-255	Unassigned

IPv6 ND Router Advertisement Flags

Registration Procedure(s)

Standards Action or IESG Approval

Reference

[RFC5175]

Available Formats

CSV

RA Option Bit	Description	Reference
0	M - Managed Address Configuration Flag	[RFC4861]
1	O - Other Configuration Flag	[RFC4861]
2	H - Mobile IPv6 Home Agent Flag	[RFC3775]
3	Prf - Router Selection Preferences	[RFC4191]
4	Prf - Router Selection Preferences	[RFC4191]
5	P - Neighbor Discovery Proxy Flag	[RFC4389]
6	S - SNAC Router Flag (TEMPORARY - registered 2024-09-02, expires 2025-09-02)	[draft-ietf-6man-snac-router-ra-flag-01]
7-53	R - Reserved; Available for assignment	[RFC5175]
54-55	Private Experimentation	[RFC5175]

Address Registration Option Status Values

Registration Procedure(s)

Standards Action

Reference

[RFC6775][RFC9010]

Available Formats

CSV

Value	Description	Reference
0	Success	[RFC6775]
1	Duplicate Address	[RFC6775]
2	Neighbor Cache Full	[RFC6775]
3	Moved	[RFC8505]
4	Removed	[RFC8505]
5	Validation Requested	[RFC8505]
6	Duplicate Source Address	[RFC8505]
7	Invalid Source Address	[RFC8505]
8	Registered Address Topologically Incorrect	[RFC8505]
9	6LBR Registry Saturated	[RFC8505]
10	Validation Failed	[RFC8505]
11	Registration Refresh Request	[RFC-ietf-6lo-multicast-registration-19]
12	Invalid Registration	[RFC-ietf-6lo-multicast-registration-19]
13-63	Unassigned	[RFC9010]

6LoWPAN Capability Bits

Registration Procedure(s)

IETF Review or IESG Approval

Reference

[RFC7400]

Available Formats

CSV

Bit	Description	Reference
0-7	Reserved for Experimental Use	[RFC7400]
8	X flag: Registration for Unicast, Multicast, and Anycast Addresses Supported	[RFC-ietf-6lo-multicast-registration-19]
9	AP-ND Enabled (1 bit)	[RFC8928]
10	EDA Support (D bit)	[RFC8505]
11	6LR capable (L bit)	[RFC8505]
12	6LBR capable (B bit)	[RFC8505]
13	Routing Registrar (P bit)	[RFC8505]
14	EARO support (E bit)	[RFC8505]
15	GHC capable bit (G bit)	[RFC7400]
16-47	Unassigned

IPv6 Neighbor Discovery Prefix Information Option Flags

Registration Procedure(s)

Standards Action

Reference

[RFC8425]

Available Formats

CSV

PIO Option Bit	Description	Reference
0	L - On-link Flag	[RFC4861]
1	A - Autonomous Address Configuration Flag	[RFC4861]
2	R - Router Address Flag	[RFC6275]
3	P - DHCPv6-PD preferred flag	[RFC-ietf-6man-pio-pflag-12]
4-7	Reserved

Address Registration Option Flags

Registration Procedure(s)

IETF Review or IESG Approval

Reference

Available Formats

CSV

Bit Number	Description	Reference
0-1	Unassigned
2-3	P-Field (2 bits)	[RFC-ietf-6lo-multicast-registration-19, Section 14.1]
4	Unassigned
6	R Flag	[RFC8505]
7	T Flag	[RFC8505]

Address Registration Option I-Field

Registration Procedure(s)

IETF Review or IESG Approval

Reference