Appendixes
Appendix A: ICMP Types and Codes
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 | Code | Description |
|
|
| Reference |
|
|
|
|
|
|
|
|
0 | Echo Reply | 0 | No Code |
|
|
| RFC792 |
3 | Destination Unreachable | 0 | Net Unreachable |
|
| RFC792 | |
|
| 1 | Host Unreachable |
|
| RFC792 | |
|
| 2 | Protocol Unreachable |
| RFC792 | ||
|
| 3 | Port Unreachable |
|
| RFC792 | |
|
| 4 | Fragmentation | Needed | and | RFC792 | |
|
|
| Don't Fragment was Set |
|
| ||
|
| 5 | Source Route Failed |
|
| RFC792 | |
|
| 6 | Destination Network Unknown | RFC792 | |||
|
| 7 | Destination Host Unknown | RFC792 | |||
|
| 8 | Source Host Isolated |
| RFC792 | ||
|
| 9 | Communication |
| with | RFC792 | |
|
|
| Destination | Network | is |
| |
|
|
| Administratively Prohibited |
| |||
|
| 10 | Communication |
| with | RFC792 | |
|
|
| Destination | Host | is |
| |
|
|
| Administratively Prohibited |
| |||
|
| 11 | Destination |
| Network | RFC792 | |
|
|
| Unreachable | for | Type | of |
|
|
|
| Service |
|
|
|
|
|
| 12 | Destination Host Unreachable | RFC792 | |||
|
|
| for Type of Service |
|
|
| |
|
| 13 | Communication |
|
| RFC1812 | |
|
|
| Administratively Prohibited |
| |||
|
| 14 | Host Precedence Violation | RFC1812 | |||
|
| 15 | Precedence cutoff in effect | RFC1812 | |||
4 | Source Quench | 0 | No Code |
|
|
| RFC792 |
5 | Redirect | 0 | Redirect Datagram | for | the | RFC792 | |
|
|
| Network (or subnet) |
|
|
| |
