ICMP types


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Appendix C. ICMP types

This is a complete listing of all ICMP types. Note the reference pointing to the RFC or person who introduced the type and code. For a complete and absolute up to date listing of all ICMP types and codes, look at the icmp-parameters document at Internet Assigned Numbers Authority.


Iptables and netfilter uses ICMP type 255 internally since it is not reserved for any real usage, and most likely will never have any real usage. If you set a rule to match iptables -A INPUT -p icmp --icmp-type 255 -j DROP, this will DROP all ICMP packets. It is in other words used to match all ICMP types.

Table C-1. ICMP types

00Echo Replyx RFC792
30Network Unreachable xRFC792
31Host Unreachable xRFC792
32Protocol Unreachable xRFC792
33Port Unreachable xRFC792
34Fragmentation needed but no frag. bit set xRFC792
35Source routing failed xRFC792
36Destination network unknown xRFC792
37Destination host unknown xRFC792
38Source host isolated (obsolete) xRFC792
39Destination network administratively prohibited xRFC792
310Destination host administratively prohibited xRFC792
311Network unreachable for TOS xRFC792
312Host unreachable for TOS xRFC792
313Communication administratively prohibited by filtering xRFC1812
314Host precedence violation xRFC1812
315Precedence cutoff in effect xRFC1812
40Source quench  RFC792
50Redirect for network  RFC792
51Redirect for host   
52Redirect for TOS and network  RFC792
53Redirect for TOS and host  RFC792
80Echo requestx RFC792
90Router advertisement - Normal router advertisement  RFC1256
916Router advertisement - Does not route common traffic  RFC2002
100Route selection  RFC1256
110TTL equals 0 during transit xRFC792
111TTL equals 0 during reassembly xRFC792
120IP header bad (catchall error) xRFC792
121Required options missing xRFC1108
122IP Header bad length xRFC792
130Timestamp request (obsolete)x RFC792
14 Timestamp reply (obsolete)x RFC792
150Information request (obsolete)x RFC792
160Information reply (obsolete)x RFC792
170Address mask requestx RFC950
180Address mask replyx RFC950
20-29 Reserved for robustness experiment  Zaw-Sing Su
300Traceroutex RFC1393
310Datagram Conversion Error xRFC1475
320Mobile Host Redirect  David Johnson
330IPv6 Where-Are-Youx Bill Simpson
340IPv6 I-Am-Herex Bill Simpson
350Mobile Registration Requestx Bill Simpson
360Mobile Registration Replyx Bill Simpson
390SKIP  Tom Markson
400Photuris  RFC2521