ICMP TYPE NUMBERS

The Internet Control Message Protocol (ICMP) has many messages that are identified by a "type" field. Here's the numbers from RFC-1700. 

Type    Name                                    Reference
----    -------------------------               ---------
  0     Echo Reply                               [RFC792]
  1     Unassigned                                  [JBP]
  2     Unassigned                                  [JBP]
  3     Destination Unreachable                  [RFC792]
  4     Source Quench                            [RFC792]
  5     Redirect                                 [RFC792]
  6     Alternate Host Address                      [JBP]
  7     Unassigned                                  [JBP]
  8     Echo                                     [RFC792]
  9     Router Advertisement                    [RFC1256]
 10     Router Selection                        [RFC1256]
 11     Time Exceeded                            [RFC792]
 12     Parameter Problem                        [RFC792]
 13     Timestamp                                [RFC792]
 14     Timestamp Reply                          [RFC792]
 15     Information Request                      [RFC792]
 16     Information Reply                        [RFC792]
 17     Address Mask Request                     [RFC950]
 18     Address 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              [David Johnson]
 33     IPv6 Where-Are-You                 [Bill Simpson]
 34     IPv6 I-Am-Here                     [Bill Simpson]
 35     Mobile Registration Request        [Bill Simpson]
 36     Mobile Registration Reply          [Bill Simpson]
 37-255 Reserved                                    [JBP]