This is a list of the IP protocol numbers found in the 8-bit Protocol field of the IPv4 header and the 8-bit Next Header field of the IPv6 header. It is an identifier for the encapsulated protocol and determines the layout of the data that immediately follows the header. Because both fields are eight bits wide, the possible values are limited to the 256 values from 0 (0x00) to 255 (0xFF), of which just over half had been allocated as of 2025.[update]

Protocol numbers are maintained and published by the Internet Assigned Numbers Authority (IANA).

HexProtocol NumberKeywordProtocolReferences/RFC
0x000HOPOPTIPv6 Hop-by-Hop OptionRFC
0x011ICMPInternet Control Message ProtocolRFC
0x022IGMPInternet Group Management ProtocolRFC
0x033GGPGateway-to-Gateway ProtocolRFC
0x044IP-in-IPIP in IP (encapsulation)RFC
0x055STInternet Stream ProtocolRFC , RFC
0x066TCPTransmission Control ProtocolRFC
0x077CBTCore-based treesRFC
0x088EGPExterior Gateway ProtocolRFC
0x099IGPInterior gateway protocol (any private interior gateway, for example Cisco's IGRP)
0x0A10BBN-RCC-MONBBN RCC Monitoring
0x0B11NVP-IINetwork Voice ProtocolRFC
0x0C12PUPXerox PUP
0x0D13ARGUSARGUS
0x0E14EMCONEMCON
0x0F15XNETCross Net DebuggerIEN 158
0x1016CHAOSChaos
0x1117UDPUser Datagram ProtocolRFC
0x1218MUXMultiplexingIEN 90
0x1319DCN-MEASDCN Measurement Subsystems
0x1420HMPHost Monitoring ProtocolRFC
0x1521PRMPacket Radio Measurement
0x1622XNS-IDPXEROX NS IDP
0x1723TRUNK-1Trunk-1
0x1824TRUNK-2Trunk-2
0x1925LEAF-1Leaf-1
0x1A26LEAF-2Leaf-2
0x1B27RDPReliable Data ProtocolRFC
0x1C28IRTPInternet Reliable Transaction ProtocolRFC
0x1D29ISO-TP4ISO Transport Protocol Class 4RFC
0x1E30NETBLTBulk Data Transfer ProtocolRFC
0x1F31MFE-NSPMFE Network Services Protocol
0x2032MERIT-INPMERIT Internodal Protocol
0x2133DCCPDatagram Congestion Control ProtocolRFC
0x22343PCThird Party Connect Protocol
0x2335IDPRInter-Domain Policy Routing ProtocolRFC
0x2436XTPXpress Transport Protocol
0x2537DDPDatagram Delivery Protocol
0x2638IDPR-CMTPIDPR Control Message Transport Protocol
0x2739TP++TP++ Transport Protocol
0x2840ILIL Transport Protocol
0x2941IPv6IPv6 Encapsulation (6to4 and 6in4)RFC
0x2A42SDRPSource Demand Routing ProtocolRFC
0x2B43IPv6-RouteRouting Header for IPv6RFC
0x2C44IPv6-FragFragment Header for IPv6RFC
0x2D45IDRPInter-Domain Routing Protocol
0x2E46RSVPResource Reservation ProtocolRFC
0x2F47GREGeneric Routing EncapsulationRFC , RFC
0x3048DSRDynamic Source Routing ProtocolRFC
0x3149BNABurroughs Network Architecture
0x3250ESPEncapsulating Security PayloadRFC
0x3351AHAuthentication HeaderRFC
0x3452I-NLSPIntegrated Net Layer Security ProtocolTUBA
0x3553SwIPeSwIPeRFC
0x3654NARPNBMA Address Resolution ProtocolRFC
0x3755MOBILEIP Mobility (Min Encap)RFC
0x3856TLSPTransport Layer Security Protocol (using Kryptonet key management)
0x3957SKIPSimple Key-Management for Internet ProtocolRFC
0x3A58IPv6-ICMPICMP for IPv6RFC , RFC
0x3B59IPv6-NoNxtNo Next Header for IPv6RFC
0x3C60IPv6-OptsDestination Options for IPv6RFC
0x3D61Any host internal protocol
0x3E62CFTPCFTP
0x3F63Any local network
0x4064SAT-EXPAKSATNET and Backroom EXPAK
0x4165KRYPTOLANKryptolan
0x4266RVDMIT Remote Virtual Disk Protocol
0x4367IPPCInternet Pluribus Packet Core
0x4468Any distributed file system
0x4569SAT-MONSATNET Monitoring
0x4670VISAVISA Protocol
0x4771IPCUInternet Packet Core Utility
0x4872CPNXComputer Protocol Network Executive
0x4973CPHBComputer Protocol Heart Beat
0x4A74WSNWang Span Network
0x4B75PVPPacket Video Protocol
0x4C76BR-SAT-MONBackroom SATNET Monitoring
0x4D77SUN-NDSUN ND PROTOCOL-Temporary
0x4E78WB-MONWIDEBAND Monitoring
0x4F79WB-EXPAKWIDEBAND EXPAK
0x5080ISO-IPInternational Organization for Standardization Internet Protocol
0x5181VMTPVersatile Message Transaction ProtocolRFC
0x5282SECURE-VMTPSecure Versatile Message Transaction ProtocolRFC
0x5383VINESVINES
0x5484TTPTTP (Transaction Transport Protocol) (obsoleted March 2023)
0x5484IPTMInternet Protocol Traffic Manager
0x5585NSFNET-IGPNSFNET-IGP
0x5686DGPDissimilar Gateway Protocol
0x5787TCFTCF
0x5888EIGRPEIGRPInformational RFC
0x5989OSPFOpen Shortest Path FirstRFC
0x5A90Sprite-RPCSprite RPC Protocol
0x5B91LARPLocus Address Resolution Protocol
0x5C92MTPMulticast Transport Protocol
0x5D93AX.25AX.25
0x5E94OSKA9Q NOS compatible IP over IP tunneling
0x5F95MICPMobile Internetworking Control Protocol
0x6096SCC-SPSemaphore Communications Sec. Pro
0x6197ETHERIPEthernet-within-IP EncapsulationRFC
0x6298ENCAPEncapsulation HeaderRFC
0x6399Any private encryption scheme
0x64100GMTPGMTP
0x65101IFMPIpsilon Flow Management Protocol
0x66102PNNIPNNI over IP
0x67103PIMProtocol Independent Multicast
0x68104ARISIBM's ARIS (Aggregate Route IP Switching) Protocol
0x69105SCPSSCPS (Space Communications Protocol Standards)SCPS-TP
0x6A106QNXQNX
0x6B107A/NActive Networks
0x6C108IPCompIP Payload Compression ProtocolRFC
0x6D109SNPSitara Networks Protocol
0x6E110Compaq-PeerCompaq Peer Protocol
0x6F111IPX-in-IPIPX in IP
0x70112VRRPVirtual Router Redundancy Protocol, Common Address Redundancy Protocol (not IANA assigned)RFC
0x71113PGMPGM Reliable Transport ProtocolRFC
0x72114Any 0-hop protocol
0x73115L2TPLayer Two Tunneling Protocol Version 3RFC
0x74116DDXD-II Data Exchange (DDX)
0x75117IATPInteractive Agent Transfer Protocol
0x76118STPSchedule Transfer Protocol
0x77119SRPSpectraLink Radio Protocol
0x78120UTIUniversal Transport Interface Protocol
0x79121SMPSimple Message Protocol
0x7A122SMSimple Multicast Protocol
0x7B123PTPPerformance Transparency Protocol
0x7C124IS-IS over IPv4Intermediate System to Intermediate System (IS-IS) Protocol over IPv4RFC and RFC
0x7D125FIREFlexible Intra-AS Routing Environment
0x7E126CRTPCombat Radio Transport Protocol
0x7F127CRUDPCombat Radio User Datagram
0x80128SSCOPMCEService-Specific Connection-Oriented Protocol in a Multilink and Connectionless Environment
0x81129IPLT
0x82130SPSSecure Packet Shield
0x83131PIPEPrivate IP Encapsulation within IP
0x84132SCTPStream Control Transmission ProtocolRFC
0x85133FCFibre Channel
0x86134RSVP-E2E-IGNOREReservation Protocol (RSVP) End-to-End IgnoreRFC
0x87135Mobility HeaderMobility Extension Header for IPv6RFC
0x88136UDPLiteLightweight User Datagram ProtocolRFC
0x89137MPLS-in-IPMultiprotocol Label Switching Encapsulated in IPRFC , RFC
0x8A138manetMANET ProtocolsRFC
0x8B139HIPHost Identity ProtocolRFC
0x8C140Shim6Site Multihoming by IPv6 IntermediationRFC
0x8D141WESPWrapped Encapsulating Security PayloadRFC
0x8E142ROHCRobust Header CompressionRFC
0x8F143EthernetSegment Routing over IPv6RFC
0x90144AGGFRAGAGGFRAG Encapsulation Payload for ESPRFC
0x91145NSHNetwork Service Header
0x92146HomaHoma transport protocol,
0x93147BIT-EMUBit-stream EmulationRFC
0x94-0xFC148-252Unassigned
0xFD-0xFE253-254Use for experimentation and testingRFC
0xFF255Reserved

See also