IP Protocol Numbers
Searchable reference of IP protocol numbers — the IPv4 Protocol field and IPv6 Next Header field — with IPv6 extension-header flagging.
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IP protocol number reference table
| Number | Hex | Keyword | Protocol name | Reference | IPv6 ext. header |
|---|---|---|---|---|---|
| 0 | 0x00 | HOPOPT | IPv6 Hop-by-Hop Option | RFC 8200 | yes |
| 1 | 0x01 | ICMP | Internet Control Message Protocol | RFC 792 | no |
| 2 | 0x02 | IGMP | Internet Group Management Protocol | RFC 1112 | no |
| 3 | 0x03 | GGP | Gateway-to-Gateway Protocol | RFC 823 | no |
| 4 | 0x04 | IPv4 | IPv4 encapsulation | RFC 2003 | no |
| 5 | 0x05 | ST | Internet Stream Protocol | RFC 1819 | no |
| 6 | 0x06 | TCP | Transmission Control Protocol | RFC 9293 | no |
| 8 | 0x08 | EGP | Exterior Gateway Protocol | RFC 888 | no |
| 9 | 0x09 | IGP | any private interior gateway (e.g. Cisco IGRP) | IANA | no |
| 17 | 0x11 | UDP | User Datagram Protocol | RFC 768 | no |
| 27 | 0x1B | RDP | Reliable Data Protocol | RFC 908 | no |
| 33 | 0x21 | DCCP | Datagram Congestion Control Protocol | RFC 4340 | no |
| 41 | 0x29 | IPv6 | IPv6 encapsulation | RFC 2473 | no |
| 43 | 0x2B | IPv6-Route | Routing Header for IPv6 | RFC 8200 | yes |
| 44 | 0x2C | IPv6-Frag | Fragment Header for IPv6 | RFC 8200 | yes |
| 46 | 0x2E | RSVP | Resource Reservation Protocol | RFC 2205, RFC 3209 | no |
| 47 | 0x2F | GRE | Generic Routing Encapsulation | RFC 2784 | no |
| 50 | 0x32 | ESP | Encapsulating Security Payload | RFC 4303 | yes |
| 51 | 0x33 | AH | Authentication Header | RFC 4302 | yes |
| 58 | 0x3A | IPv6-ICMP | ICMP for IPv6 | RFC 4443 | no |
| 59 | 0x3B | IPv6-NoNxt | No Next Header for IPv6 | RFC 8200 | no — ends the header chain |
| 60 | 0x3C | IPv6-Opts | Destination Options for IPv6 | RFC 8200 | yes |
| 88 | 0x58 | EIGRP | Enhanced Interior Gateway Routing Protocol | RFC 7868 | no |
| 89 | 0x59 | OSPFIGP | Open Shortest Path First | RFC 2328, RFC 5340 | no |
| 94 | 0x5E | IPIP | IP-within-IP Encapsulation Protocol | IANA | no |
| 97 | 0x61 | ETHERIP | Ethernet-within-IP Encapsulation | RFC 3378 | no |
| 98 | 0x62 | ENCAP | Encapsulation Header | RFC 1241 | no |
| 103 | 0x67 | PIM | Protocol Independent Multicast | RFC 7761 | no |
| 108 | 0x6C | IPComp | IP Payload Compression Protocol | RFC 3173 | no |
| 112 | 0x70 | VRRP | Virtual Router Redundancy Protocol | RFC 9568 | no |
| 115 | 0x73 | L2TP | Layer Two Tunneling Protocol version 3 | RFC 3931 | no |
| 124 | 0x7C | ISIS over IPv4 | IS-IS over IPv4 | IANA | no |
| 132 | 0x84 | SCTP | Stream Control Transmission Protocol | RFC 9260 | no |
| 133 | 0x85 | FC | Fibre Channel | RFC 6172 | no |
| 135 | 0x87 | Mobility Header | IPv6 Mobility Header | RFC 6275 | yes |
| 136 | 0x88 | UDPLite | Lightweight User Datagram Protocol | RFC 3828 | no |
| 137 | 0x89 | MPLS-in-IP | MPLS-in-IP | RFC 4023 | no |
| 138 | 0x8A | manet | MANET Protocols | RFC 5498 | no |
| 139 | 0x8B | HIP | Host Identity Protocol | RFC 7401 | yes |
| 140 | 0x8C | Shim6 | Shim6 Protocol | RFC 5533 | yes |
| 141 | 0x8D | WESP | Wrapped Encapsulating Security Payload | RFC 5840 | no |
| 142 | 0x8E | ROHC | Robust Header Compression | RFC 5858 | no |
| 143 | 0x8F | Ethernet | Ethernet (SRv6 / segment routing) | RFC 8986 | no |
| 144 | 0x90 | AGGFRAG | AGGFRAG encapsulation payload for ESP | RFC 9347 | no |
| 145 | 0x91 | NSH | Network Service Header | RFC 9491 | no |
| 146 | 0x92 | Homa | Homa | IANA | no |
| 147 | 0x93 | BIT-EMU | Bit-stream Emulation | RFC 9801 | yes |
| 253 | 0xFD | — | Use for experimentation and testing | RFC 3692 | yes |
| 254 | 0xFE | — | Use for experimentation and testing | RFC 3692 | yes |
| 255 | 0xFF | Reserved | Reserved | IANA | no |
How it works
Reference for the 8-bit value in the IPv4 header "Protocol" field and the IPv6 header "Next Header" field, from the IANA Assigned Internet Protocol Numbers registry (registry last updated 2026-03-09; verified 2026-09-15). This table is a curated subset of the values operators meet often; only entries verified as correct are included, and an absent value may still be assigned. Number and keyword follow the registry; the protocol name is a curated display label. Search by decimal number, by 0x-style hex, or by a word in the keyword or name. In IPv6 the same field is the Next Header field. The IPv6 extension header column mirrors the IPv6 Extension Header attribute of that registry — 0, 43, 44, 50, 51, 60, 135, 139, 140, 147 and the experimental values 253 and 254 are marked there. Value 59 means "no next header": it ends the header chain and is not marked as an extension header, so it is shown separately. Protocol numbers 253 and 254 are reserved for experimentation and testing (RFC 3692); 255 is reserved. The Reference column is a curated protocol reference: the current protocol-specification RFC where a clear one exists (for example RFC 9568 for VRRP, RFC 9260 for SCTP), otherwise the RFCs the registry cites, and IANA when the assignment is backed only by an IANA contact or submission. The full table works without JavaScript; search and the lookup panel need JavaScript.