| Code | Field | Name | Description |
|---|---|---|---|
| 1 | Internet Protocol Numbers | Internet Control Message Protocol (ICMP) | |
| 3 | Internet Protocol Numbers | Gateway-Gateway Protocol (GGP) | |
| 6 | Internet Protocol Numbers | Transmission Control Protocol (TCP) | |
| 8 | Internet Protocol Numbers | Exterior Gateway Protocol (EGP) | |
| 12 | Internet Protocol Numbers | PARC Universal Packet Protocol (PUP) | |
| 17 | Internet Protocol Numbers | User Datagram Protocol (UDP) | |
| 20 | Internet Protocol Numbers | Host Monitoring Protocol (HMP) | |
| 27 | Internet Protocol Numbers | Reliable Datagram Protocol (RDP) | |
| 46 | Internet Protocol Numbers | Reservation Protocol (RSVP) QoS | |
| 47 | Internet Protocol Numbers | General Routing Encapsulation (PPTP data over GRE) | |
| 50 | Internet Protocol Numbers | Encapsulation Security Payload (ESP) IPSec | |
| 51 | Internet Protocol Numbers | Authentication Header (AH) IPSec | |
| 66 | Internet Protocol Numbers | MIT Remote Virtual Disk (RVD) | |
| 88 | Internet Protocol Numbers | Internet Group Management Protocol (IGMP) | |
| 89 | Internet Protocol Numbers | OSPF Open Shortest Path First |