| 0 | 0 | Echo Reply | x | | RFC792 |
| 3 | 0 | Network Unreachable | | x | RFC792 |
| 3 | 1 | Host Unreachable | | x | RFC792 |
| 3 | 2 | Protocol Unreachable | | x | RFC792 |
| 3 | 3 | Port Unreachable | | x | RFC792 |
| 3 | 4 | Fragmentation needed but no frag. bit set | | x | RFC792 |
| 3 | 5 | Source routing failed | | x | RFC792 |
| 3 | 6 | Destination network unknown | | x | RFC792 |
| 3 | 7 | Destination host unknown | | x | RFC792 |
| 3 | 8 | Source host isolated (obsolete) | | x | RFC792 |
| 3 | 9 | Destination network administratively prohibited | | x | RFC792 |
| 3 | 10 | Destination host administratively prohibited | | x | RFC792 |
| 3 | 11 | Network unreachable for TOS | | x | RFC792 |
| 3 | 12 | Host unreachable for TOS | | x | RFC792 |
| 3 | 13 | Communication administratively prohibited by filtering | | x | RFC1812 |
| 3 | 14 | Host precedence violation | | x | RFC1812 |
| 3 | 15 | Precedence cutoff in effect | | x | RFC1812 |
| 4 | 0 | Source quench | | | RFC792 |
| 5 | 0 | Redirect for network | | | RFC792 |
| 5 | 1 | Redirect for host | | | |
| 5 | 2 | Redirect for TOS and network | | | RFC792 |
| 5 | 3 | Redirect for TOS and host | | | RFC792 |
| 8 | 0 | Echo request | x | | RFC792 |
| 9 | 0 | Router advertisement - Normal router advertisement | | | RFC1256 |
| 9 | 16 | Router advertisement - Does not route common traffic | | | RFC2002 |
| 10 | 0 | Route selection | | | RFC1256 |
| 11 | 0 | TTL equals 0 during transit | | x | RFC792 |
| 11 | 1 | TTL equals 0 during reassembly | | x | RFC792 |
| 12 | 0 | IP header bad (catchall error) | | x | RFC792 |
| 12 | 1 | Required options missing | | x | RFC1108 |
| 12 | 2 | IP Header bad length | | x | RFC792 |
| 13 | 0 | Timestamp request (obsolete) | x | | RFC792 |
| 14 | | Timestamp reply (obsolete) | x | | RFC792 |
| 15 | 0 | Information request (obsolete) | x | | RFC792 |
| 16 | 0 | Information reply (obsolete) | x | | RFC792 |
| 17 | 0 | Address mask request | x | | RFC950 |
| 18 | 0 | Address mask reply | x | | RFC950 |
| 20-29 | | Reserved for robustness experiment | | | Zaw-Sing Su |
| 30 | 0 | Traceroute | x | | RFC1393 |
| 31 | 0 | Datagram Conversion Error | | x | RFC1475 |
| 32 | 0 | Mobile Host Redirect | | | David Johnson |
| 33 | 0 | IPv6 Where-Are-You | x | | Bill Simpson |
| 34 | 0 | IPv6 I-Am-Here | x | | Bill Simpson |
| 35 | 0 | Mobile Registration Request | x | | Bill Simpson |
| 36 | 0 | Mobile Registration Reply | x | | Bill Simpson |
| 39 | 0 | SKIP | | | Tom Markson |
| 40 | 0 | Photuris | | | RFC2521 |
