2026-01-05 IESG Approval or Standards Action The Internet Control Message Protocol (ICMP) has many messages that are identified by a "type" field. When this registry is modified, the YANG module "iana-icmpv4-types" must be updated as defined in . 0 Echo Reply 1 Unassigned 2 Unassigned 3 Destination Unreachable 4 Source Quench (Deprecated) 5 Redirect 6 Alternate Host Address (Deprecated) 7 Unassigned 8 Echo 9 Router Advertisement 10 Router Solicitation 11 Time Exceeded 12 Parameter Problem 13 Timestamp 14 Timestamp Reply 15 Information Request (Deprecated) 16 Information Reply (Deprecated) 17 Address Mask Request (Deprecated) 18 Address Mask Reply (Deprecated) 19 Reserved (for Security) 20-29 Reserved (for Robustness Experiment) 30 Traceroute (Deprecated) 31 Datagram Conversion Error (Deprecated) 32 Mobile Host Redirect (Deprecated) 33 IPv6 Where-Are-You (Deprecated) 34 IPv6 I-Am-Here (Deprecated) 35 Mobile Registration Request (Deprecated) 36 Mobile Registration Reply (Deprecated) 37 Domain Name Request (Deprecated) 38 Domain Name Reply (Deprecated) 39 SKIP (Deprecated) 40 Photuris 41 ICMP messages utilized by experimental mobility protocols such as Seamoby 42 Extended Echo Request 43 Extended Echo Reply 44-252 Unassigned 253 RFC3692-style Experiment 1 254 RFC3692-style Experiment 2 255 Reserved Many of these ICMP types have a "code" field. Here we list the types again with their assigned code fields. IESG Approval or Standards Action 0 No Code IESG Approval or Standards Action 0 Net Unreachable 1 Host Unreachable 2 Protocol Unreachable 3 Port Unreachable 4 Fragmentation Needed and Don't Fragment was Set 5 Source Route Failed 6 Destination Network Unknown 7 Destination Host Unknown 8 Source Host Isolated 9 Communication with Destination Network is Administratively Prohibited 10 Communication with Destination Host is Administratively Prohibited 11 Destination Network Unreachable for Type of Service 12 Destination Host Unreachable for Type of Service 13 Communication Administratively Prohibited 14 Host Precedence Violation 15 Precedence cutoff in effect 0 No Code IESG Approval or Standards Action 0 Redirect Datagram for the Network (or subnet) 1 Redirect Datagram for the Host 2 Redirect Datagram for the Type of Service and Network 3 Redirect Datagram for the Type of Service and Host 0 Alternate Address for Host IESG Approval or Standards Action 0 No Code IESG Approval or Standards Action 0 Normal router advertisement 16 Does not route common traffic IESG Approval or Standards Action 0 No Code IESG Approval or Standards Action 0 Time to Live exceeded in Transit 1 Fragment Reassembly Time Exceeded IESG Approval or Standards Action 0 Pointer indicates the error 1 Missing a Required Option 2 Bad Length IESG Approval or Standards Action 0 No Code IESG Approval or Standards Action 0 No Code 0 No Code 0 No Code 0 No Code 0 No Code IESG Approval or Standards Action 0 Bad SPI 1 Authentication Failed 2 Decompression Failed 3 Decryption Failed 4 Need Authentication 5 Need Authorization Specification Required or IESG Approval 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 Standards Action or IESG Approval Standards Action or IESG Approval It is only appropriate to use these values in explicitly- configured experiments; they MUST NOT be shipped as defaults in implementations. See RFC 3692 for details. 0-246 First Come First Served 247-255 Private Use 1 MPLS Label Stack Class 2 Interface Information Object 3 Interface Identification Object 4 Extended Information 5 Node Identification Object 6 Reflect All 7-246 Unassigned 247-255 Reserved for Private Use First Come First Served 0 Reserved 1 Incoming MPLS Label Stack 2-246 Unassigned 247-255 Reserved for private use 0-1 Interface Role field 2 Unallocated - allocatable with Standards Action 3 Unallocated - allocatable with Standards Action 4 ifIndex included 5 IP Address Sub-object included 6 Name Sub-object included 7 MTU included 0 Incoming IP Interface 1 Sub-IP Component of Incoming IP Interface 2 Outgoing IP Interface 3 IP Next-hop First Come First Served 0 Reserved 1 Identifies Interface By Name 2 Identifies Interface By Index 3 Identifies Interface By Address 4-255 Unassigned Standards Action 0 Reserved 1 Pointer First Come First Served 0 Request 1 Reply - No Error 2 Reply - Unsupported Object 3-255 Unassigned Jon Postel mailto:postel&isi.edu 1995-09 David Johnson Tom Markson mailto:markson&osmosys.incog.com 1995-09 Bill Simpson mailto:Bill.Simpson&um.cc.umich.edu 1995-10 Zaw-Sing Su mailto:ZSu&TSCA.ISTC.SRI.COM