Das Internet Control Message Protocol (ICMP), definiert in der RFC792, stellt Informationen genereller Art über Probleme mit IP-Daten bereit oder dient als einfache Form der Zeitstempel oder Echo Aktionen.



8

16

32 bits

Type

Code

Checksum

Type and Code dependently



Type

Nachrichtentyp:

Type

Meaning

Reference

3

Destination Unreachable

[RFC792]

4

Source Quench

[RFC792]

5

Redirect

[RFC792]

6

Alternate Host Address

[JBP]

8 / 0

Echo Request / Echo Reply

[RFC792]

9 / 10

Router Advertisement / Router Solicitation

[RFC1256]

11

Time Exceeded

[RFC792]

12

Parameter Problem

[RFC792]

13 / 14

Timestamp Request / Timestamp Reply

[RFC792]

15 / 16

Information Request / Information Reply

[RFC792]

17 / 18

Adress Mask Request / Adress Mask Reply

[RFC950]

19

"Reserved" (for Security)

[Solo]

20..29

"Reserved" (for Robustness Experiment)

[ZSu]

30

Traceroute

[RFC1393]

31

Datagram Conversion Error

[RFC1475]

32

Mobile Host Redirect

[Johnson]

33 / 34

IPv6 Where-Are-You / IPv6 I-Am-Here

[Simpson]

35 / 36

Mobile Registration Request / Mobile Registration Reply

[Simpson]

37 / 38

Domain Name Request / Domain Name Reply

[RFC1788]

39

SKIP

[Markson]

40

Photuris

[RFC2521]

41..255

"Reserved" for future use

...

Code

Type spezifische Information

Checksum

Checksumme über ICMP-packet plus einem sogenannten Pseudoheader zum Schutz gegen fehlende Segmente (Source IP-Adresse, Destination IP-Adresse, Transport protocol, ICMP-length)

Type and Code dependently

je nach Type und Code (see RFC792 / RFC 1700)