Internet Control Message Protocol (ICMP) Parameters

Last Updated: 2023-07-10

The Internet Control Message Protocol (ICMP) has many messages that are identified by a "type" field. Many of these ICMP types have a "code" field. Here we list the types with their assigned code fields.

 

TYPE	NAME	CODES	REFERENCE
0	Echo Reply	Codes   0      No  Code	[RFC792]
1	Unassigned		[JBP]
2	Unassigned		[JBP]
3	Destination Unreachable	Codes   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  [RFC1122]   7      Destination  Host  Unknown  [RFC1122]   8      Source  Host  Isolated  [RFC1122]   9      Communication  with  Destination  Network  is  Administratively  Prohibited  [RFC1122] 10      Communication  with  Destination  Host  is  Administratively  Prohibited  [RFC1122] 11      Destination  Network  Unreachable  for  Type  of  Service  [RFC1122] 12      Destination  Host  Unreachable  for  Type  of  Service  [RFC1122] 13      Communication  Administratively  Prohibited  [RFC1812] 14      Host  Precedence  Violation  [RFC1812] 15      Precedence  cutoff  in  effect  [RFC1812]	[RFC792][RFC2780]
4	Source Quench (Deprecated)	Codes   0      No  Code	[RFC792][RFC6633]
5	Redirect	Codes   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	[RFC792]
6	Alternate Host Address (Deprecated)	Codes   0      Alternate  Address  for  Host	[JBP][RFC6918]
7	Unassigned		[JBP]
8	Echo	Codes   0      No  Code	[RFC792]
9	Router Advertisement	Codes   0      Normal  router  advertisement 16      Does  not  route  common  traffic  [RFC2002]	[RFC1256][RFC2780][RFC3344]
10	Router Selection	Codes   0      No  Code	[RFC1256]
11	Time Exceeded	Codes   0      Time  to  Live  exceeded  in  Transit   1      Fragment  Reassembly  Time  Exceeded	[RFC792]
12	Parameter Problem	Codes   0      Pointer  indicates  the  error   1      Missing  a  Required  Option  [RFC1108]   2      Bad  Length	[RFC792]
13	Timestamp	Codes   0      No  Code	[RFC792]
14	Timestamp Reply	Codes   0      No  Code	[RFC792]
15	Information Request (Deprecated)	Codes   0      No  Code	[RFC792][RFC6918]
16	Information Reply (Deprecated)	Codes   0      No  Code	[RFC792][RFC6918]
17	Address Mask Request (Deprecated)	Codes   0      No  Code	[RFC950][RFC6918]
18	Address Mask Reply (Deprecated)	Codes   0      No  Code	[RFC950][RFC6918]
19	Reserved (for Security)		[SOLO]
20-29	Reserved (for Robustness Experiment)		[ZSu]
30	Traceroute (Deprecated)		[RFC1393][RFC6918]
31	Datagram Conversion Error (Deprecated)		[RFC1475][RFC6918]
32	Mobile Host Redirect (Deprecated)		[David_Johnson][RFC6918]
33	IPv6 Where-Are-You (Deprecated)		[Bill Simpson][RFC6918]
34	IPv6 I-Am-Here (Deprecated)		[Bill Simpson][RFC6918]
35	Mobile Registration Request (Deprecated)		[Bill Simpson][RFC6918]
36	Mobile Registration Reply (Deprecated)		[Bill Simpson][RFC6918]
37	Domain Name Request (Deprecated)		[Bill Simpson][RFC6918]
38	Domain Name Reply (Deprecated)		[Bill Simpson][RFC6918]
39	SKIP (Deprecated)		[Markson][RFC6918]
40	Photuris	Codes   0      Bad  SPI   1      Authentication  Failed   2      Decompression  Failed   3      Decryption  Failed   4      Need  Authentication   5      Need  Authorization	[RFC792]
41	Experimental	ICMP  messages  utilized  by  experimental  mobility  protocols  such  as  Seamoby	[RFC4065]
42	Extended Echo Request	Codes   0      No  Error	[RFC8335]
43	Extended Echo Reply	Codes   0      No  Error   1      Malformed  Query   2      No  Such  Interface   3      No  Such  Table  Entry   4      Multiple  Interfaces  Satisfy  Query	[RFC8335]
253	RFC3692-style Experiment 1		[RFC4727]
254	RFC3692-style Experiment 2		[RFC4727]
255	Reserved		[JBP]

 

REFERENCES

REFERENCE NOTES [RFC792] Postel, J., "Internet Control Message Protocol", STD 5, RFC 792, USC/Information Sciences Institute, September 1981. [RFC950] Mogul, J., and J. Postel, "Internet Standard Subnetting Procedure", STD 5, RFC 950, Stanford, USC/Information Sciences Institute, August 1985. [RFC1108] Kent, S., "U.S. Department of Defense Security Options for the Internet Protocol", RFC 1108, November 1991. [RFC1122] Braden, R., "Requirements for Internet Hosts -- Communication Layers", RFC1122, October 1989. [RFC1256] Deering, S., Editor, "ICMP Router Discovery Messages", RFC 1256, Xerox PARC, September 1991. [RFC1393] Malkin, G., "Traceroute Using an IP Option", RFC 1393, Xylogics, Inc., January 1993. [RFC1475] Ullmann, R., "TP/IX: The Next Internet", RFC 1475, Process Software Corporation, June 1993. [RFC1788] W. Simpson, "ICMP Domain Name Messages", RFC 1788, April 1995. [RFC1812] Baker, F., "Requirements for IP Version 4 Routers", RFC 1812, Cisco Systems, June 1995. [RFC2002] C. Perkins, Editor, "IP Mobility Support", RFC 2002, October 1996. [RFC2521] P. Karn and W. Simpson, "ICMP Security Failures Messages", RFC 2521, March 1999. [RFC2780] Paxson, V., "IANA Allocation Guidelines For Values In the Internet Protocol and Related Headers", RFC2780, March 2000. [RFC3344] Perkins, D., "IP Mobility Support for IPv4", RFC3344, August 2002. [RFC4065] Kempf, J., "Instructions for Seamoby and Experimental Mobility Protocol IANA Allocations", RFC4065, July 2005. [RFC4727] Fenner, B., "Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP Headers", RFC4727, November 2006. [RFC6633] Gont, F., "Deprecation of ICMP Source Quench Messages", RFC6633, May 2012. [RFC6918] Gont, F., "Formally Deprecating Some ICMPv4 Message Types", RFC6918, April 2013. [RFC8335] Bonica, R., "PROBE: A Utility for Probing Interfaces", RFC8335, February 2018.

 

PEOPLE

REFERENCE NOTES [JBP] Jon Postel, , September 1995. [David Johnson] David Johnson [Markson] Tom Markson, , September 1995. [Simpson] Bill Simpson, , October 1995. [Solo]   [ZSu] Zaw-Sing Su