Im IP-Header gibt es ein Feld, das Informationen über den Typ des Payloads speichert. In IPv4 ist es das Feld "Protocol", in der Version 6 wird das Feld "Next Header" genannt.
Das Protocol-Feld ist ein Byte lang. Über die Information in diesem Feld, kann der Empfänger die Nutzlast erkennen. Beispiele für Protokollnummern sind die 1 für ICMP, die 6 für TCP und die Protokollnummer 17 für UDP.
Assigned Internet Protocol Numbers
Decimal Keyword Protocol References
------- ------- -------- ----------
0 HOPOPT IPv6 Hop-by-Hop Option [RFC1883]
1 ICMP Internet Control Message [RFC792]
2 IGMP Internet Group Management [RFC1112]
3 GGP Gateway-to-Gateway [RFC823]
4 IP IP in IP (encapsulation) [RFC2003]
5 ST Stream [RFC1190,RFC1819]
6 TCP Transmission Control [RFC793]
7 CBT CBT [Ballardie]
8 EGP Exterior Gateway Protocol [RFC888,DLM1]
9 IGP any private interior gateway [IANA]
(used by Cisco for their IGRP)
10 BBN-RCC-MON BBN RCC Monitoring [SGC]
11 NVP-II Network Voice Protocol [RFC741,SC3]
12 PUP PUP [PUP,XEROX]
13 ARGUS ARGUS [RWS4]
14 EMCON EMCON [BN7]
15 XNET Cross Net Debugger [IEN158,JFH2]
16 CHAOS Chaos [NC3]
17 UDP User Datagram [RFC768,JBP]
18 MUX Multiplexing [IEN90,JBP]
19 DCN-MEAS DCN Measurement Subsystems [DLM1]
20 HMP Host Monitoring [RFC869,RH6]
21 PRM Packet Radio Measurement [ZSU]
22 XNS-IDP XEROX NS IDP [ETHERNET,XEROX]
23 TRUNK-1 Trunk-1 [BWB6]
24 TRUNK-2 Trunk-2 [BWB6]
25 LEAF-1 Leaf-1 [BWB6]
26 LEAF-2 Leaf-2 [BWB6]
27 RDP Reliable Data Protocol [RFC908,RH6]
28 IRTP Internet Reliable Transaction [RFC938,TXM]
29 ISO-TP4 ISO Transport Protocol Class 4 [RFC905,RC77]
30 NETBLT Bulk Data Transfer Protocol [RFC969,DDC1]
31 MFE-NSP MFE Network Services Protocol [MFENET,BCH2]
32 MERIT-INP MERIT Internodal Protocol [HWB]
33 DCCP Datagram Congestion Control Protocol [RFC-ietf-dccp-spec-11.txt]
34 3PC Third Party Connect Protocol [SAF3]
35 IDPR Inter-Domain Policy Routing Protocol [MXS1]
36 XTP XTP [GXC]
37 DDP Datagram Delivery Protocol [WXC]
38 IDPR-CMTP IDPR Control Message Transport Proto [MXS1]
39 TP++ TP++ Transport Protocol [DXF]
40 IL IL Transport Protocol [Presotto]
41 IPv6 Ipv6 [Deering]
42 SDRP Source Demand Routing Protocol [DXE1]
43 IPv6-Route Routing Header for IPv6 [Deering]
44 IPv6-Frag Fragment Header for IPv6 [Deering]
45 IDRP Inter-Domain Routing Protocol [Sue Hares]
46 RSVP Reservation Protocol [Bob Braden]
47 GRE General Routing Encapsulation [Tony Li]
48 MHRP Mobile Host Routing Protocol[David Johnson]
49 BNA BNA [Gary Salamon]
50 ESP Encap Security Payload [RFC2406]
51 AH Authentication Header [RFC2402]
52 I-NLSP Integrated Net Layer Security TUBA [GLENN]
53 SWIPE IP with Encryption [JI6]
54 NARP NBMA Address Resolution Protocol [RFC1735]
55 MOBILE IP Mobility [Perkins]
56 TLSP Transport Layer Security Protocol [Oberg]
using Kryptonet key management
57 SKIP SKIP [Markson]
58 IPv6-ICMP ICMP for IPv6 [RFC1883]
59 IPv6-NoNxt No Next Header for IPv6 [RFC1883]
60 IPv6-Opts Destination Options for IPv6 [RFC1883]
61 any host internal protocol [IANA]
62 CFTP CFTP [CFTP,HCF2]
63 any local network [IANA]
64 SAT-EXPAK SATNET and Backroom EXPAK [SHB]
65 KRYPTOLAN Kryptolan [PXL1]
66 RVD MIT Remote Virtual Disk Protocol [MBG]
67 IPPC Internet Pluribus Packet Core [SHB]
68 any distributed file system [IANA]
69 SAT-MON SATNET Monitoring [SHB]
70 VISA VISA Protocol [GXT1]
71 IPCV Internet Packet Core Utility [SHB]
72 CPNX Computer Protocol Network Executive [DXM2]
73 CPHB Computer Protocol Heart Beat [DXM2]
74 WSN Wang Span Network [VXD]
75 PVP Packet Video Protocol [SC3]
76 BR-SAT-MON Backroom SATNET Monitoring [SHB]
77 SUN-ND SUN ND PROTOCOL-Temporary [WM3]
78 WB-MON WIDEBAND Monitoring [SHB]
79 WB-EXPAK WIDEBAND EXPAK [SHB]
80 ISO-IP ISO Internet Protocol [MTR]
81 VMTP VMTP [DRC3]
82 SECURE-VMTP SECURE-VMTP [DRC3]
83 VINES VINES [BXH]
84 TTP TTP [JXS]
85 NSFNET-IGP NSFNET-IGP [HWB]
86 DGP Dissimilar Gateway Protocol [DGP,ML109]
87 TCF TCF [GAL5]
88 EIGRP EIGRP [CISCO,GXS]
89 OSPFIGP OSPFIGP [RFC1583,JTM4]
90 Sprite-RPC Sprite RPC Protocol [SPRITE,BXW]
91 LARP Locus Address Resolution Protocol [BXH]
92 MTP Multicast Transport Protocol [SXA]
93 AX.25 AX.25 Frames [BK29]
94 IPIP IP-within-IP Encapsulation Protocol [JI6]
95 MICP Mobile Internetworking Control Pro. [JI6]
96 SCC-SP Semaphore Communications Sec. Pro. [HXH]
97 ETHERIP Ethernet-within-IP Encapsulation [RFC3378]
98 ENCAP Encapsulation Header [RFC1241,RXB3]
99 any private encryption scheme [IANA]
100 GMTP GMTP [RXB5]
101 IFMP Ipsilon Flow Management Protocol [Hinden]
102 PNNI PNNI over IP [Callon]
103 PIM Protocol Independent Multicast [Farinacci]
104 ARIS ARIS [Feldman]
105 SCPS SCPS [Durst]
106 QNX QNX [Hunter]
107 A/N Active Networks [Braden]
108 IPComp IP Payload Compression Protocol [RFC2393]
109 SNP Sitara Networks Protocol [Sridhar]
110 Compaq-Peer Compaq Peer Protocol [Volpe]
111 IPX-in-IP IPX in IP [Lee]
112 VRRP Virtual Router Redundancy Protocol [RFC3768]
113 PGM PGM Reliable Transport Protocol [Speakman]
114 any 0-hop protocol [IANA]
115 L2TP Layer Two Tunneling Protocol [Aboba]
116 DDX D-II Data Exchange (DDX) [Worley]
117 IATP Interactive Agent Transfer Protocol [Murphy]
118 STP Schedule Transfer Protocol [JMP]
119 SRP SpectraLink Radio Protocol [Hamilton]
120 UTI UTI [Lothberg]
121 SMP Simple Message Protocol [Ekblad]
122 SM SM [Crowcroft]
123 PTP Performance Transparency Protocol [Welzl]
124 ISIS over IPv4 [Przygienda]
125 FIRE [Partridge]
126 CRTP Combat Radio Transport Protocol [Sautter]
127 CRUDP Combat Radio User Datagram [Sautter]
128 SSCOPMCE [Waber]
129 IPLT [Hollbach]
130 SPS Secure Packet Shield [McIntosh]
131 PIPE Private IP Encapsulation within IP [Petri]
132 SCTP Stream Control Transmission Protocol [Stewart]
133 FC Fibre Channel [Rajagopal]
134 RSVP-E2E-IGNORE [RFC3175]
135 Mobility Header [RFC3775]
136 UDPLite [RFC3828]
137 MPLS-in-IP [RFC4023]
138-252 Unassigned [IANA]
253 Use for experimentation and testing [RFC3692]
254 Use for experimentation and testing [RFC3692]
255 Reserved [IANA]
Quelle: IANA