In the Internet Protocol version 4 (IPv4) RFC 791 there is a field
called "Protocol" to identify the next level protocol. This is an 8
bit field. In Internet Protocol version 6 (IPv6) RFC 8200, this field
is called the "Next Header" field.
References: RFC 5237, RFC 7045
| Value | Defined by | Name | Description | References |
|---|---|---|---|---|
| 0 | IANA | HOPOPT | IPv6 Hop-by-Hop Option | RFC 8200 |
| 1 | IANA | ICMP | Internet Control Message | RFC 792 |
| 2 | IANA | IGMP | Internet Group Management | RFC 1112 |
| 3 | IANA | GGP | Gateway-to-Gateway | RFC 823 |
| 4 | IANA | IPv4 | IPv4 encapsulation | RFC 2003 |
| 5 | IANA | ST | Stream | RFC 1190, RFC 1819 |
| 6 | IANA | TCP | Transmission Control | RFC 793, RFC 9293 |
| 7 | IANA | CBT | CBT | Tony Ballardie |
| 8 | IANA | EGP | Exterior Gateway Protocol | David Mills, RFC 888 |
| 9 | IANA | IGP | any private interior gateway (used by Cisco for their IGRP) |
Internet Assigned Numbers Authority |
| 10 | IANA | BBN-RCC-MON | BBN RCC Monitoring | Steve Chipman |
| 11 | IANA | NVP-II | Network Voice Protocol | Steve Casner, RFC 741 |
| 12 | IANA | PUP | PUP | Boggs, D., J. Shoch, E. Taft, and R. Metcalfe, "PUP: An Internetwork Architecture", XEROX Palo Alto Research Center, CSL-79-10, July 1979; also in IEEE Transactions on Communication, Volume COM-28, Number 4, April 1980., [XEROX] |
| 13 | IANA | ARGUS (deprecated) | ARGUS | Robert W. Scheifler |
| 14 | IANA | EMCON | EMCON | Bich Nguyen, <mystery contact> |
| 15 | IANA | XNET | Cross Net Debugger | Jack Haverty, Haverty, J., "XNET Formats for Internet Protocol Version 4", IEN 158, October 1980. |
| 16 | IANA | CHAOS | Chaos | J. Noel Chiappa |
| 17 | IANA | UDP | User Datagram | Jon Postel, RFC 768 |
| 18 | IANA | MUX | Multiplexing | Jon Postel, Cohen, D. and J. Postel, "Multiplexing Protocol", IEN 90, USC/Information Sciences Institute, May 1979. |
| 19 | IANA | DCN-MEAS | DCN Measurement Subsystems | David Mills |
| 20 | IANA | HMP | Host Monitoring | Bob Hinden, RFC 869 |
| 21 | IANA | PRM | Packet Radio Measurement | Zaw-Sing Su |
| 22 | IANA | XNS-IDP | XEROX NS IDP | "The Ethernet, A Local Area Network: Data Link Layer and Physical Layer Specification", AA-K759B-TK, Digital Equipment Corporation, Maynard, MA. Also as: "The Ethernet - A Local Area Network", Version 1.0, Digital Equipment Corporation, Intel Corporation, Xerox Corporation, September 1980. And: "The Ethernet, A Local Area Network: Data Link Layer and Physical Layer Specifications", Digital, Intel and Xerox, November 1982. And: XEROX, "The Ethernet, A Local Area Network: Data Link Layer and Physical Layer Specification", X3T51/80-50, Xerox Corporation, Stamford, CT., October 1980., [XEROX] |
| 23 | IANA | TRUNK-1 | Trunk-1 | Barry Boehm |
| 24 | IANA | TRUNK-2 | Trunk-2 | Barry Boehm |
| 25 | IANA | LEAF-1 | Leaf-1 | Barry Boehm |
| 26 | IANA | LEAF-2 | Leaf-2 | Barry Boehm |
| 27 | IANA | RDP | Reliable Data Protocol | Bob Hinden, RFC 908 |
| 28 | IANA | IRTP | Internet Reliable Transaction | Trudy Miller, RFC 938 |
| 29 | IANA | ISO-TP4 | ISO Transport Protocol Class 4 | Robert Cole, RFC 905, <mystery contact> |
| 30 | IANA | NETBLT | Bulk Data Transfer Protocol | David Clark, RFC 969 |
| 31 | IANA | MFE-NSP | MFE Network Services Protocol | Barry Howard, Shuttleworth, B., "A Documentary of MFENet, a National Computer Network", UCRL-52317, Lawrence Livermore Labs, Livermore, California, June 1977. |
| 32 | IANA | MERIT-INP | MERIT Internodal Protocol | Hans-Werner Braun |
| 33 | IANA | DCCP | Datagram Congestion Control Protocol | RFC 4340 |
| 34 | IANA | 3PC | Third Party Connect Protocol | Stuart A. Friedberg |
| 35 | IANA | IDPR | Inter-Domain Policy Routing Protocol | Martha Steenstrup |
| 36 | IANA | XTP | XTP | Greg Chesson |
| 37 | IANA | DDP | Datagram Delivery Protocol | Wesley Craig |
| 38 | IANA | IDPR-CMTP | IDPR Control Message Transport Proto | Martha Steenstrup |
| 39 | IANA | TP++ | TP++ Transport Protocol | Dirk Fromhein |
| 40 | IANA | IL | IL Transport Protocol | Dave Presotto |
| 41 | IANA | IPv6 | IPv6 encapsulation | RFC 2473 |
| 42 | IANA | SDRP | Source Demand Routing Protocol | Deborah Estrin |
| 43 | IANA | IPv6-Route | Routing Header for IPv6 | Steve Deering |
| 44 | IANA | IPv6-Frag | Fragment Header for IPv6 | Steve Deering |
| 45 | IANA | IDRP | Inter-Domain Routing Protocol | Sue Hares |
| 46 | IANA | RSVP | Reservation Protocol | Bob Braden, RFC 2205, RFC 3209 |
| 47 | IANA | GRE | Generic Routing Encapsulation | Tony Li, RFC 2784 |
| 48 | IANA | DSR | Dynamic Source Routing Protocol | RFC 4728 |
| 49 | IANA | BNA | BNA | Gary Salamon |
| 50 | IANA | ESP | Encap Security Payload | RFC 4303 |
| 51 | IANA | AH | Authentication Header | RFC 4302 |
| 52 | IANA | I-NLSP | Integrated Net Layer Security TUBA | K. Robert Glenn |
| 53 | IANA | SWIPE (deprecated) | IP with Encryption | John Ioannidis |
| 54 | IANA | NARP | NBMA Address Resolution Protocol | RFC 1735 |
| 55 | IANA | MOBILE | IP Mobility | Charlie Perkins |
| 56 | IANA | TLSP | Transport Layer Security Protocol using Kryptonet key management |
Christer Oberg |
| 57 | IANA | SKIP | SKIP | Tom Markson |
| 58 | IANA | IPv6-ICMP | ICMP for IPv6 | RFC 8200 |
| 59 | IANA | IPv6-NoNxt | No Next Header for IPv6 | RFC 8200 |
| 60 | IANA | IPv6-Opts | Destination Options for IPv6 | RFC 8200 |
| 61 | IANA | - | any host internal protocol | Internet Assigned Numbers Authority |
| 62 | IANA | CFTP | CFTP | Harry Forsdick, Forsdick, H., "CFTP", Network Message, Bolt Beranek and Newman, January 1982. |
| 63 | IANA | - | any local network | Internet Assigned Numbers Authority |
| 64 | IANA | SAT-EXPAK | SATNET and Backroom EXPAK | Steven Blumenthal |
| 65 | IANA | KRYPTOLAN | Kryptolan | Paul Liu |
| 66 | IANA | RVD | MIT Remote Virtual Disk Protocol | Michael Greenwald |
| 67 | IANA | IPPC | Internet Pluribus Packet Core | Steven Blumenthal |
| 68 | IANA | - | any distributed file system | Internet Assigned Numbers Authority |
| 69 | IANA | SAT-MON | SATNET Monitoring | Steven Blumenthal |
| 70 | IANA | VISA | VISA Protocol | Gene Tsudik |
| 71 | IANA | IPCV | Internet Packet Core Utility | Steven Blumenthal |
| 72 | IANA | CPNX | Computer Protocol Network Executive | David Mittnacht |
| 73 | IANA | CPHB | Computer Protocol Heart Beat | David Mittnacht |
| 74 | IANA | WSN | Wang Span Network | Victor Dafoulas |
| 75 | IANA | PVP | Packet Video Protocol | Steve Casner |
| 76 | IANA | BR-SAT-MON | Backroom SATNET Monitoring | Steven Blumenthal |
| 77 | IANA | SUN-ND | SUN ND PROTOCOL-Temporary | William Melohn |
| 78 | IANA | WB-MON | WIDEBAND Monitoring | Steven Blumenthal |
| 79 | IANA | WB-EXPAK | WIDEBAND EXPAK | Steven Blumenthal |
| 80 | IANA | ISO-IP | ISO Internet Protocol | Marshall T. Rose |
| 81 | IANA | VMTP | VMTP | Dave Cheriton |
| 82 | IANA | SECURE-VMTP | SECURE-VMTP | Dave Cheriton |
| 83 | IANA | VINES | VINES | Brian Horn |
| 84 | IANA | IPTM | Internet Protocol Traffic Manager | Jim Stevens |
| 85 | IANA | NSFNET-IGP | NSFNET-IGP | Hans-Werner Braun |
| 86 | IANA | DGP | Dissimilar Gateway Protocol | Mike Little, M/A-COM Government Systems, "Dissimilar Gateway Protocol Specification, Draft Version", Contract no. CS901145, November 16, 1987. |
| 87 | IANA | TCF | TCF | Guillermo A. Loyola |
| 88 | IANA | EIGRP | EIGRP | RFC 7868 |
| 89 | IANA | OSPFIGP | OSPFIGP | John Moy, RFC 1583, RFC 2328, RFC 5340 |
| 90 | IANA | Sprite-RPC | Sprite RPC Protocol | Bruce Willins, Welch, B., "The Sprite Remote Procedure Call System", Technical Report, UCB/Computer Science Dept., 86/302, University of California at Berkeley, June 1986. |
| 91 | IANA | LARP | Locus Address Resolution Protocol | Brian Horn |
| 92 | IANA | MTP | Multicast Transport Protocol | Susie Armstrong |
| 93 | IANA | AX.25 | AX.25 Frames | Brian Kantor |
| 94 | IANA | IPIP | IP-within-IP Encapsulation Protocol | John Ioannidis |
| 95 | IANA | MICP (deprecated) | Mobile Internetworking Control Pro. | John Ioannidis |
| 96 | IANA | SCC-SP | Semaphore Communications Sec. Pro. | Howard Hart |
| 97 | IANA | ETHERIP | Ethernet-within-IP Encapsulation | RFC 3378 |
| 98 | IANA | ENCAP | Encapsulation Header | Robert Woodburn, RFC 1241 |
| 99 | IANA | - | any private encryption scheme | Internet Assigned Numbers Authority |
| 100 | IANA | GMTP | GMTP | [RXB5] |
| 101 | IANA | IFMP | Ipsilon Flow Management Protocol | Bob Hinden, November 1995, 1997. |
| 102 | IANA | PNNI | PNNI over IP | Ross Callon |
| 103 | IANA | PIM | Protocol Independent Multicast | Dino Farinacci, RFC 7761 |
| 104 | IANA | ARIS | ARIS | Nancy Feldman |
| 105 | IANA | SCPS | SCPS | Robert Durst |
| 106 | IANA | QNX | QNX | Michael Hunter |
| 107 | IANA | A/N | Active Networks | Bob Braden |
| 108 | IANA | IPComp | IP Payload Compression Protocol | RFC 2393 |
| 109 | IANA | SNP | Sitara Networks Protocol | Manickam R. Sridhar |
| 110 | IANA | Compaq-Peer | Compaq Peer Protocol | Victor Volpe |
| 111 | IANA | IPX-in-IP | IPX in IP | CJ Lee |
| 112 | OpenBSD | CARP | Common Address Redundancy Protocol | www.openbsd.org |
| 112 | IANA | VRRP | Virtual Router Redundancy Protocol | RFC 5798 |
| 113 | IANA | PGM | PGM Reliable Transport Protocol | Tony Speakman |
| 114 | IANA | - | any 0-hop protocol | Internet Assigned Numbers Authority |
| 115 | IANA | L2TP | Layer Two Tunneling Protocol | Bernard Aboba, RFC 3931 |
| 116 | IANA | DDX | D-II Data Exchange (DDX) | John Worley |
| 117 | IANA | IATP | Interactive Agent Transfer Protocol | John Murphy |
| 118 | IANA | STP | Schedule Transfer Protocol | Jean-Michel Pittet |
| 119 | IANA | SRP | SpectraLink Radio Protocol | Mark Hamilton |
| 120 | IANA | UTI | UTI | Peter Lothberg |
| 121 | IANA | SMP | Simple Message Protocol | Leif Ekblad |
| 122 | IANA | SM (deprecated) | Simple Multicast Protocol | Jon Crowcroft |
| 123 | IANA | PTP | Performance Transparency Protocol | Michael Welzl |
| 124 | IANA | ISIS over IPv4 | - | Tony Przygienda |
| 125 | IANA | FIRE | - | Criag Partridge |
| 126 | IANA | CRTP | Combat Radio Transport Protocol | Robert Sautter |
| 127 | IANA | CRUDP | Combat Radio User Datagram | Robert Sautter |
| 128 | IANA | SSCOPMCE | - | Kurt Waber |
| 129 | IANA | IPLT | - | [Hollbach] |
| 130 | IANA | SPS | Secure Packet Shield | Bill McIntosh |
| 131 | IANA | PIPE | Private IP Encapsulation within IP | Bernhard Petri |
| 132 | IANA | SCTP | Stream Control Transmission Protocol | Randall R. Stewart |
| 133 | IANA | FC | Fibre Channel | Murali Rajagopal, RFC 6172 |
| 134 | IANA | RSVP-E2E-IGNORE | - | RFC 3175 |
| 135 | IANA | Mobility Header | - | RFC 6275 |
| 136 | IANA | UDPLite | - | RFC 3828 |
| 137 | IANA | MPLS-in-IP | - | RFC 4023 |
| 138 | IANA | manet | MANET Protocols | RFC 5498 |
| 139 | IANA | HIP | Host Identity Protocol | RFC 7401 |
| 140 | IANA | Shim6 | Shim6 Protocol | RFC 5533 |
| 141 | IANA | WESP | Wrapped Encapsulating Security Payload | RFC 5840 |
| 142 | IANA | ROHC | Robust Header Compression | RFC 5858 |
| 143 | IANA | Ethernet | Ethernet | RFC 8986 |
| 144 | IANA | AGGFRAG | AGGFRAG encapsulation payload for ESP | RFC 9347 |
| 253 | IANA | - | Use for experimentation and testing | RFC 3692 |
| 254 | IANA | - | Use for experimentation and testing | RFC 3692 |
| 255 | IANA | Reserved | - | Internet Assigned Numbers Authority |