Internet Assigned Numbers Authority

Protocol Numbers

Last Updated
Available Formats



Plain text

Registry included below

Assigned Internet Protocol Numbers

Registration Procedure(s)
IESG Approval or Standards Action
In the Internet Protocol version 4 (IPv4) [RFC791] there is a field
called "Protocol" to identify the next level protocol.  This is an 8
bit field.  In Internet Protocol version 6 (IPv6) [RFC8200], this field 
is called the "Next Header" field.
Values that are also IPv6 Extension Header Types should be listed in the 
IPv6 Extension Header Types registry at [IANA registry ipv6-parameters].
Available Formats

Decimal Keyword Protocol IPv6 Extension Header Reference
0 HOPOPT IPv6 Hop-by-Hop Option Y [RFC8200]
1 ICMP Internet Control Message [RFC792]
2 IGMP Internet Group Management [RFC1112]
3 GGP Gateway-to-Gateway [RFC823]
4 IPv4 IPv4 encapsulation [RFC2003]
5 ST Stream [RFC1190][RFC1819]
6 TCP Transmission Control [RFC9293]
7 CBT CBT [Tony_Ballardie]
8 EGP Exterior Gateway Protocol [RFC888][David_Mills]
9 IGP any private interior gateway (used by Cisco for their IGRP) [Internet_Assigned_Numbers_Authority]
10 BBN-RCC-MON BBN RCC Monitoring [Steve_Chipman]
11 NVP-II Network Voice Protocol [RFC741][Steve_Casner]
12 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 ARGUS (deprecated) ARGUS [Robert_W_Scheifler]
14 EMCON EMCON [Bich_Nguyen]
15 XNET Cross Net Debugger [Haverty, J., "XNET Formats for Internet Protocol Version 4", IEN 158, October 1980.][Jack_Haverty]
16 CHAOS Chaos [J_Noel_Chiappa]
17 UDP User Datagram [RFC768][Jon_Postel]
18 MUX Multiplexing [Cohen, D. and J. Postel, "Multiplexing Protocol", IEN 90, USC/Information Sciences Institute, May 1979.][Jon_Postel]
19 DCN-MEAS DCN Measurement Subsystems [David_Mills]
20 HMP Host Monitoring [RFC869][Bob_Hinden]
21 PRM Packet Radio Measurement [Zaw_Sing_Su]
22 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 TRUNK-1 Trunk-1 [Barry_Boehm]
24 TRUNK-2 Trunk-2 [Barry_Boehm]
25 LEAF-1 Leaf-1 [Barry_Boehm]
26 LEAF-2 Leaf-2 [Barry_Boehm]
27 RDP Reliable Data Protocol [RFC908][Bob_Hinden]
28 IRTP Internet Reliable Transaction [RFC938][Trudy_Miller]
29 ISO-TP4 ISO Transport Protocol Class 4 [RFC905][Robert_Cole]
30 NETBLT Bulk Data Transfer Protocol [RFC969][David_Clark]
31 MFE-NSP MFE Network Services Protocol [Shuttleworth, B., "A Documentary of MFENet, a National Computer Network", UCRL-52317, Lawrence Livermore Labs, Livermore, California, June 1977.][Barry_Howard]
32 MERIT-INP MERIT Internodal Protocol [Hans_Werner_Braun]
33 DCCP Datagram Congestion Control Protocol [RFC4340]
34 3PC Third Party Connect Protocol [Stuart_A_Friedberg]
35 IDPR Inter-Domain Policy Routing Protocol [Martha_Steenstrup]
36 XTP XTP [Greg_Chesson]
37 DDP Datagram Delivery Protocol [Wesley_Craig]
38 IDPR-CMTP IDPR Control Message Transport Proto [Martha_Steenstrup]
39 TP++ TP++ Transport Protocol [Dirk_Fromhein]
40 IL IL Transport Protocol [Dave_Presotto]
41 IPv6 IPv6 encapsulation [RFC2473]
42 SDRP Source Demand Routing Protocol [Deborah_Estrin]
43 IPv6-Route Routing Header for IPv6 Y [Steve_Deering]
44 IPv6-Frag Fragment Header for IPv6 Y [Steve_Deering]
45 IDRP Inter-Domain Routing Protocol [Sue_Hares]
46 RSVP Reservation Protocol [RFC2205][RFC3209][Bob_Braden]
47 GRE Generic Routing Encapsulation [RFC2784][Tony_Li]
48 DSR Dynamic Source Routing Protocol [RFC4728]
49 BNA BNA [Gary Salamon]
50 ESP Encap Security Payload Y [RFC4303]
51 AH Authentication Header Y [RFC4302]
52 I-NLSP Integrated Net Layer Security TUBA [K_Robert_Glenn]
53 SWIPE (deprecated) IP with Encryption [John_Ioannidis]
54 NARP NBMA Address Resolution Protocol [RFC1735]
55 Min-IPv4 Minimal IPv4 Encapsulation [RFC2004][Charlie_Perkins]
56 TLSP Transport Layer Security Protocol using Kryptonet key management [Christer_Oberg]
57 SKIP SKIP [Tom_Markson]
58 IPv6-ICMP ICMP for IPv6 [RFC8200]
59 IPv6-NoNxt No Next Header for IPv6 [RFC8200]
60 IPv6-Opts Destination Options for IPv6 Y [RFC8200]
61 any host internal protocol [Internet_Assigned_Numbers_Authority]
62 CFTP CFTP [Forsdick, H., "CFTP", Network Message, Bolt Beranek and Newman, January 1982.][Harry_Forsdick]
63 any local network [Internet_Assigned_Numbers_Authority]
64 SAT-EXPAK SATNET and Backroom EXPAK [Steven_Blumenthal]
65 KRYPTOLAN Kryptolan [Paul Liu]
66 RVD MIT Remote Virtual Disk Protocol [Michael_Greenwald]
67 IPPC Internet Pluribus Packet Core [Steven_Blumenthal]
68 any distributed file system [Internet_Assigned_Numbers_Authority]
69 SAT-MON SATNET Monitoring [Steven_Blumenthal]
70 VISA VISA Protocol [Gene_Tsudik]
71 IPCV Internet Packet Core Utility [Steven_Blumenthal]
72 CPNX Computer Protocol Network Executive [David Mittnacht]
73 CPHB Computer Protocol Heart Beat [David Mittnacht]
74 WSN Wang Span Network [Victor Dafoulas]
75 PVP Packet Video Protocol [Steve_Casner]
76 BR-SAT-MON Backroom SATNET Monitoring [Steven_Blumenthal]
77 SUN-ND SUN ND PROTOCOL-Temporary [William_Melohn]
78 WB-MON WIDEBAND Monitoring [Steven_Blumenthal]
79 WB-EXPAK WIDEBAND EXPAK [Steven_Blumenthal]
80 ISO-IP ISO Internet Protocol [Marshall_T_Rose]
81 VMTP VMTP [Dave_Cheriton]
83 VINES VINES [Brian Horn]
84 IPTM Internet Protocol Traffic Manager [Jim_Stevens][1]
85 NSFNET-IGP NSFNET-IGP [Hans_Werner_Braun]
86 DGP Dissimilar Gateway Protocol [M/A-COM Government Systems, "Dissimilar Gateway Protocol Specification, Draft Version", Contract no. CS901145, November 16, 1987.][Mike_Little]
87 TCF TCF [Guillermo_A_Loyola]
89 OSPFIGP OSPFIGP [RFC1583][RFC2328][RFC5340][John_Moy]
90 Sprite-RPC Sprite RPC Protocol [Welch, B., "The Sprite Remote Procedure Call System", Technical Report, UCB/Computer Science Dept., 86/302, University of California at Berkeley, June 1986.][Bruce Willins]
91 LARP Locus Address Resolution Protocol [Brian Horn]
92 MTP Multicast Transport Protocol [Susie_Armstrong]
93 AX.25 AX.25 Frames [Brian_Kantor]
94 IPIP IP-within-IP Encapsulation Protocol [John_Ioannidis]
95 MICP (deprecated) Mobile Internetworking Control Pro. [John_Ioannidis]
96 SCC-SP Semaphore Communications Sec. Pro. [Howard_Hart]
97 ETHERIP Ethernet-within-IP Encapsulation [RFC3378]
98 ENCAP Encapsulation Header [RFC1241][Robert_Woodburn]
99 any private encryption scheme [Internet_Assigned_Numbers_Authority]
100 GMTP GMTP [[RXB5]]
101 IFMP Ipsilon Flow Management Protocol [Bob_Hinden][November 1995, 1997.]
102 PNNI PNNI over IP [Ross_Callon]
103 PIM Protocol Independent Multicast [RFC7761][Dino_Farinacci]
104 ARIS ARIS [Nancy_Feldman]
105 SCPS SCPS [Robert_Durst]
106 QNX QNX [Michael_Hunter]
107 A/N Active Networks [Bob_Braden]
108 IPComp IP Payload Compression Protocol [RFC2393]
109 SNP Sitara Networks Protocol [Manickam_R_Sridhar]
110 Compaq-Peer Compaq Peer Protocol [Victor_Volpe]
111 IPX-in-IP IPX in IP [CJ_Lee]
112 VRRP Virtual Router Redundancy Protocol [RFC9568]
113 PGM PGM Reliable Transport Protocol [Tony_Speakman]
114 any 0-hop protocol [Internet_Assigned_Numbers_Authority]
115 L2TP Layer Two Tunneling Protocol [RFC3931][Bernard_Aboba]
116 DDX D-II Data Exchange (DDX) [John_Worley]
117 IATP Interactive Agent Transfer Protocol [John_Murphy]
118 STP Schedule Transfer Protocol [Jean_Michel_Pittet]
119 SRP SpectraLink Radio Protocol [Mark_Hamilton]
120 UTI UTI [Peter_Lothberg]
121 SMP Simple Message Protocol [Leif_Ekblad]
122 SM (deprecated) Simple Multicast Protocol [Jon_Crowcroft][draft-perlman-simple-multicast]
123 PTP Performance Transparency Protocol [Michael_Welzl]
124 ISIS over IPv4 [Tony_Przygienda]
125 FIRE [Criag_Partridge]
126 CRTP Combat Radio Transport Protocol [Robert_Sautter]
127 CRUDP Combat Radio User Datagram [Robert_Sautter]
128 SSCOPMCE [Kurt_Waber]
129 IPLT [[Hollbach]]
130 SPS Secure Packet Shield [Bill_McIntosh]
131 PIPE Private IP Encapsulation within IP [Bernhard_Petri]
132 SCTP Stream Control Transmission Protocol [Randall_R_Stewart]
133 FC Fibre Channel [Murali_Rajagopal][RFC6172]
135 Mobility Header Y [RFC6275]
136 UDPLite [RFC3828]
137 MPLS-in-IP [RFC4023]
138 manet MANET Protocols [RFC5498]
139 HIP Host Identity Protocol Y [RFC7401]
140 Shim6 Shim6 Protocol Y [RFC5533]
141 WESP Wrapped Encapsulating Security Payload [RFC5840]
142 ROHC Robust Header Compression [RFC5858]
143 Ethernet Ethernet [RFC8986]
144 AGGFRAG AGGFRAG encapsulation payload for ESP [RFC9347]
145 NSH Network Service Header N [RFC9491]
146-252 Unassigned [Internet_Assigned_Numbers_Authority]
253 Use for experimentation and testing Y [RFC3692]
254 Use for experimentation and testing Y [RFC3692]
255 Reserved [Internet_Assigned_Numbers_Authority]

Contact Information

ID Name Contact URI Last Updated
[Barry_Boehm] Barry Boehm mailto:boehm&
[Barry_Howard] Barry Howard mailto:Howard&
[Bernard_Aboba] Bernard Aboba mailto:bernarda& 1998-04
[Bernhard_Petri] Bernhard Petri mailto:bernhard.petri& 2012-07-09
[Bich_Nguyen] Bich Nguyen mailto:bitnguyen& 2023-01-09
[Bill_McIntosh] Bill McIntosh mailto:BMcIntosh&
[Bob_Braden] Bob Braden mailto:braden& 1997-07
[Bob_Hinden] Bob Hinden mailto:bob.hinden& 2013-02-17
[Brian_Kantor] Brian Kantor mailto:brian&
[CJ_Lee] CJ Lee mailto:cj_lee& 1997-10
[Charlie_Perkins] Charlie Perkins mailto:perk& 1994-10
[Christer_Oberg] Christer Oberg mailto:chg& 1994-10
[Criag_Partridge] Criag Partridge mailto:craig& 1999-08
[Dave_Cheriton] Dave Cheriton mailto:cheriton&
[Dave_Presotto] Dave Presotto mailto:presotto& 1995-07
[David_Clark] David Clark mailto:ddc&
[David_Mills] David Mills mailto:Mills&
[Deborah_Estrin] Deborah Estrin mailto:estrin&
[Dino_Farinacci] Dino Farinacci mailto:dino& 1996-03
[Dirk_Fromhein] Dirk Fromhein mailto:df&
[Gene_Tsudik] Gene Tsudik mailto:tsudik&
[Greg_Chesson] Greg Chesson mailto:Greg&
[Guillermo_A_Loyola] Guillermo A. Loyola mailto:LOYOLA&
[Hans_Werner_Braun] Hans-Werner Braun mailto:HWB&
[Harry_Forsdick] Harry Forsdick mailto:Forsdick&
[Howard_Hart] Howard Hart mailto:hch&
[Internet_Assigned_Numbers_Authority] Internet Assigned Numbers Authority mailto:iana& 1995-06
[J_Noel_Chiappa] J. Noel Chiappa mailto:JNC&
[Jack_Haverty] Jack Haverty mailto:jhaverty&
[Jean_Michel_Pittet] Jean-Michel Pittet mailto:jmp& 1998-11
[Jim_Stevens] Jim Stevens mailto:jasteven& 2011-01-26
[John_Ioannidis] John Ioannidis mailto:ji& 2015-01-06
[John_Moy] John Moy mailto:jmoy&
[John_Murphy] John Murphy mailto:john.m.murphy& 1998-10
[John_Worley] John Worley mailto:worley& 1998-06
[Jon_Crowcroft] Jon Crowcroft mailto:jon& 1999-06
[Jon_Postel] Jon Postel mailto:postel&
[K_Robert_Glenn] K. Robert Glenn mailto:glenn&
[Kurt_Waber] Kurt Waber mailto:kurt.waber& 1999-08
[Leif_Ekblad] Leif Ekblad mailto:leif& 2012-08-21
[Manickam_R_Sridhar] Manickam R. Sridhar mailto:msridhar& 1997-09
[Mark_Hamilton] Mark Hamilton mailto:mah& 1998-11
[Marshall_T_Rose] Marshall T. Rose mailto:mrose&
[Martha_Steenstrup] Martha Steenstrup mailto:MSteenst&
[Michael_Greenwald] Michael Greenwald mailto:Greenwald&
[Michael_Hunter] Michael Hunter mailto:mphunter& 1997-07
[Michael_Welzl] Michael Welzl mailto:michael& 1999-08
[Mike_Little] Mike Little mailto:little&
[Murali_Rajagopal] Murali Rajagopal mailto:murali& 2000-05
[Nancy_Feldman] Nancy Feldman mailto:nkf& 1997-01
[Peter_Lothberg] Peter Lothberg mailto:roll& 1999-03
[Randall_R_Stewart] Randall R. Stewart mailto:rrs& 2000-04
[Robert_Cole] Robert Cole mailto:robert&CS.UCL.AC.UK
[Robert_Durst] Robert Durst mailto:durst& 1997-03
[Robert_Sautter] Robert Sautter mailto:rsautter& 1999-08
[Robert_W_Scheifler] Robert W. Scheifler mailto:rscheifler& 2015-10-06
[Robert_Woodburn] Robert Woodburn mailto:woody&
[Ross_Callon] Ross Callon mailto:rcallon& 1995-12
[Steve_Casner] Steve Casner mailto:casner&
[Steve_Chipman] Steve Chipman mailto:Chipman&
[Steve_Deering] Steve Deering mailto:deering& 1995-03
[Steven_Blumenthal] Steven Blumenthal mailto:BLUMENTHAL&
[Stuart_A_Friedberg] Stuart A. Friedberg mailto:stuart&
[Sue_Hares] Sue Hares mailto:skh&
[Susie_Armstrong] Susie Armstrong mailto:Armstrong.wbst128&
[Tom_Markson] Tom Markson mailto:markson& 1995-09
[Tony_Ballardie] Tony Ballardie mailto:A.Ballardie&
[Tony_Li] Tony Li 2012-10-17
[Tony_Przygienda] Tony Przygienda mailto:prz& 1999-08
[Tony_Speakman] Tony Speakman mailto:speakman& 1998-01
[Trudy_Miller] Trudy Miller mailto:Trudy&
[Victor_Volpe] Victor Volpe mailto:vvolpe& 1997-10
[Wesley_Craig] Wesley Craig mailto:Wesley.Craig&
[William_Melohn] William Melohn mailto:Melohn&
[Zaw_Sing_Su] Zaw-Sing Su mailto:ZSu&tsca.istc.sri.


Until March 2023, value 84 was also assigned to TTP (Transaction Transport Protocol).