2026-02-11 When this registry is modified, the YANG module "iana-icmpv6-types" must be updated as defined in . 0-127 (Error messages) IETF Review 128-255 (Informational messages) IETF Review 0 Reserved 1 Destination Unreachable 2 Packet Too Big 3 Time Exceeded 4 Parameter Problem 5-99 Unassigned 100 Private experimentation 101 Private experimentation 102-126 Unassigned 127 Reserved for expansion of ICMPv6 error messages 128 Echo Request 129 Echo Reply 130 Multicast Listener Query 131 Multicast Listener Report 132 Multicast Listener Done 133 Router Solicitation 134 Router Advertisement 135 Neighbor Solicitation 136 Neighbor Advertisement 137 Redirect Message 138 Router Renumbering 139 ICMP Node Information Query 140 ICMP Node Information Response 141 Inverse Neighbor Discovery Solicitation Message 142 Inverse Neighbor Discovery Advertisement Message 143 Version 2 Multicast Listener Report 144 Home Agent Address Discovery Request Message 145 Home Agent Address Discovery Reply Message 146 Mobile Prefix Solicitation 147 Mobile Prefix Advertisement 148 Certification Path Solicitation Message 149 Certification Path Advertisement Message 150 ICMP messages utilized by experimental mobility protocols such as Seamoby 151 Multicast Router Advertisement 152 Multicast Router Solicitation 153 Multicast Router Termination 154 FMIPv6 Messages 155 RPL Control Message 156 ILNPv6 Locator Update Message 157 Duplicate Address Request 158 Duplicate Address Confirmation 159 MPL Control Message 160 Extended Echo Request 161 Extended Echo Reply 162-199 Unassigned 200 Private experimentation 201 Private experimentation 202-254 Unassigned 255 Reserved for expansion of ICMPv6 informational messages 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. Standards Action or IESG Approval 0 no route to destination 1 communication with destination administratively prohibited 2 beyond scope of source address 3 address unreachable 4 port unreachable 5 source address failed ingress/egress policy 6 reject route to destination 7 Error in Source Routing Header 8 Headers too long 9 Error in P-Route Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 hop limit exceeded in transit 1 fragment reassembly time exceeded Standards Action or IESG Approval 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 4 SR Upper-layer Header Error 5 Unrecognized Next Header type encountered by intermediate node 6 Extension header too big 7 Extension header chain too long 8 Too many extension headers 9 Too many options in extension header 10 Option too big Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 Standards Action or IESG Approval 0 IETF Review 0 Router Renumbering Command 1 Router Renumbering Result 255 Sequence Number Reset Specification Required Unassigned 0 The Data field contains an IPv6 address which is the Subject of this Query. 1 The Data field contains a name which is the Subject of this Query, or is empty, as in the case of a NOOP. 2 The Data field contains an IPv4 address which is the Subject of this Query. Specification Required Unassigned 0 A successful reply. The Reply Data field may or may not be empty. 1 The Responder refuses to supply the answer. The Reply Data field will be empty. 2 The Qtype of the Query is unknown to the Responder. The Reply Data field will be empty. Standards Action 0 Standards Action 0 IESG Approval 0 IESG Approval 0 IESG Approval 0 IESG Approval 0 IETF Review or IESG Approval 0 DAR message 1 EDAR message with 64-bit ROVR field 2 EDAR message with 128-bit ROVR field 3 EDAR message with 192-bit ROVR field 4 EDAR message with 256-bit ROVR field 5-15 Unassigned IETF Review or IESG Approval 0 DAC message 1 EDAC message with 64-bit ROVR field 2 EDAC message with 128-bit ROVR field 3 EDAC message with 192-bit ROVR field 4 EDAC message with 256-bit ROVR field 5-15 Unassigned First Come First Served 0 No Error 1-255 Unassigned First Come First Served 0 No Error 1 Malformed Query 2 No Such Interface 3 No Such Table Entry 4 Multiple Interfaces Satisfy Query 5-255 Unassigned RFC Required 0 Reserved 1 Reserved 2 RtSolPr 3 PrRtAdv 4 HI - Deprecated (Unavailable for Assignment) 5 HAck - Deprecated (Unavailable for Assignment) 6-255 Unassigned RFC Required 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 . 1 Source Link-layer Address 2 Target Link-layer Address 3 Prefix Information 4 Redirected Header 5 MTU 6 NBMA Shortcut Limit Option 7 Advertisement Interval Option 8 Home Agent Information Option 9 Source Address List 10 Target Address List 11 CGA option 12 RSA Signature option 13 Timestamp option 14 Nonce option 15 Trust Anchor option 16 Certificate option 17 IP Address/Prefix Option 18 New Router Prefix Information Option 19 Link-layer Address Option 20 Neighbor Advertisement Acknowledgment Option 21 PvD ID Router Advertisement Option 22 Unassigned 23 MAP Option 24 Route Information Option 25 Recursive DNS Server Option 26 RA Flags Extension Option 27 Handover Key Request Option 28 Handover Key Reply Option 29 Handover Assist Information Option 30 Mobile Node Identifier Option 31 DNS Search List Option 32 Proxy Signature (PS) 33 Address Registration Option 34 6LoWPAN Context Option 35 Authoritative Border Router Option 36 6LoWPAN Capability Indication Option (6CIO) 37 DHCP Captive-Portal 38 PREF64 option 39 Crypto-ID Parameters Option (CIPO) 40 NDP Signature Option (NDPSO) 41 Resource Directory Address Option 42 Consistent Uptime Option 43-137 Unassigned 138 CARD Request option 139 CARD Reply option 140-143 Unassigned 144 Encrypted DNS Option 145-252 Unassigned 253 RFC3692-style Experiment 1 254 RFC3692-style Experiment 2 It is only appropriate to use these values in explicitly configured experiments; they MUST NOT be shipped as defaults in implementations. See for details. Standards Action or IESG Approval 0 Reserved 1 DER Encoded X.501 Name 2 FQDN 3 SHA-1 Subject Key Identifier (SKI) 4 SHA-224 Subject Key Identifier (SKI) 5 SHA-256 Subject Key Identifier (SKI) 6 SHA-384 Subject Key Identifier (SKI) 7 SHA-512 Subject Key Identifier (SKI) 8-252 Unassigned 253-254 Reserved for Experimental Use 255 Reserved Standards Action 0 Reserved 1 X.509v3 Certificate 2-255 Unassigned Standards Action or IESG Approval 0 Reserved 1 AN ID 2 Sector ID 3-255 Unassigned Standards Action or IESG Approval 0 Reserved 1 NAI 2 IMSI 3-255 Unassigned IETF Review 0 NOOP 1 Unused 2 Node Name 3 Node Addresses 4 IPv4 Addresses 5-255 Unassigned Standards Action or IESG Approval 0 M - Managed Address Configuration Flag 1 O - Other Configuration Flag 2 H - Mobile IPv6 Home Agent Flag 3 Prf - Router Selection Preferences 4 Prf - Router Selection Preferences 5 P - Neighbor Discovery Proxy Flag 6 S - SNAC Router Flag 7-53 R - Reserved; Available for assignment 54-55 Private Experimentation Standards Action 0 Success 1 Duplicate Address 2 Neighbor Cache Full 3 Moved 4 Removed 5 Validation Requested 6 Duplicate Source Address 7 Invalid Source Address 8 Registered Address Topologically Incorrect 9 6LBR Registry Saturated 10 Validation Failed 11 Registration Refresh Request 12 Invalid Registration 13-63 Unassigned IETF Review or IESG Approval 0-7 Reserved for Experimental Use 8 X flag: Registration for Unicast, Multicast, and Anycast Addresses Supported 9 AP-ND Enabled (A bit) 10 EDA Support (D bit) 11 6LR capable (L bit) 12 6LBR capable (B bit) 13 Routing Registrar (P bit) 14 EARO support (E bit) 15 GHC capable bit (G bit) 16 Registration for prefixes supported (F bit) 17-47 Unassigned Standards Action 0 L - On-link Flag 1 A - Autonomous Address Configuration Flag 2 R - Router Address Flag 3 P - DHCPv6-PD Preferred Flag 4-7 Reserved IETF Review or IESG Approval 0 Unassigned 1 C-Flag 2-3 P-Field (2 bits) RFC9685, Section 14.1 4-5 I-Field (2 bits) RFC8505, Section 4.1 6 R Flag 7 T Flag IETF Review or IESG Approval 0 Abstract Index for Topology Selection 1-3 Unassigned Standards Action 0 H-flag 1 L-flag 2 R-flag 3-11 Unassigned Specification Required or IESG Approval Pascal Thubert, Mohit Sethi 0 ECDSA256 NIST P-256 FIPS186-4 SHA-256 ECDSA FIPS186-4 Weierstrass, (un)compressed, MSB/msb-order, SEC1 33/65 bytes (compressed/uncompressed) 64 bytes 1 Ed25519 Curve25519 SHA-512 Ed25519 Edwards, compressed, LSB/lsb-order, 32 bytes (compressed) 64 bytes 2 ECDSA25519 Curve25519 SHA-256 ECDSA FIPS186-4 Weierstrass, (un)compressed, MSB/msb-order, 33/65 bytes (compressed/uncompressed) 64 bytes 3-255 Unassigned Standards Action 0 Registration for a Unicast Address 1 Registration for a Multicast Address 2 Registration for an Anycast Address 3 Registration for a Unicast Prefix IETF Review or IESG Approval 0-1 P-Field (2 bits) RFC9685, Section 14.1 2-7 Unassigned