# Protokoll (IP)

Das Feld Protokoll (protocol) im IPv4-Header gibt an, zu welchem Protokoll (auch „Folgeprotokoll“ genannt) die im betreffenden IPv4-Paket transportierten Nutzdaten gehören. Das Feld ist 8Bit breit und wird als vorzeichenlose Ganzzahl interpretiert. Sie kann daher Werte von 0 bis 255 (dezimal) aufnehmen. Die Werte waren im festgelegt. Seit 2002 wurde durch eine Online-Datenbank für Protokoll-Nummern bei der IANA als aktuell definiert. Allerdings kommen in Netzen auch Protokolle vor, die (noch) nicht bei der IANA registriert sind.
Im IPv6-Header gibt es dieses Feld ebenfalls, allerdings heißt es dort Next Header. Die zulässigen Werte sind die gleichen wie beim Feld protocol bei IPv4.

## Protokollnummern

| Protokollnummer | Protokoll |
| 0 | HOPOPT (IPv6 Hop-by-Hop Option) |
| 1 | ICMP (Internet Control Message Protocol) |
| 2 | IGMP (Internet Group Management Protocol) |
| 3 | GGP (Gateway-to-Gateway) |
| 4 | IP (IP in IP (encapsulation)) |
| 5 | Stream |
| 6 | TCP (Transmission Control Protocol) |
| 7 | CBT (Core Based Trees) |
| 8 | EGP (Exterior Gateway Protocol) |
| 9 | IGP (any private interior gateway) |
| 10 | BBN-RCC-MON (BBN RCC Monitoring) |
| 11 | NVP-II (Network Voice Protocol) |
| 12 | PUP |
| 13 | ARGUS |
| 14 | EMCON |
| 15 | XNET (Cross Net Debugger) |
| 16 | CHAOS |
| 17 | UDP (User Datagram Protocol) |
| 18 | Multiplexing |
| 19 | DCN-MEAS (DCN Measurement Subsystems) |
| 20 | HMP (Host Monitoring) |
| 21 | PRM (Packet Radio Measurement) |
| 22 | XNS-IDP (XEROX NS IDP) |
| 23 | TRUNK-1 |
| 24 | TRUNK-2 |
| 25 | LEAF-1 |
| 26 | LEAF-2 |
| 27 | RDP (Reliable Data Protocol) |
| 28 | IRTP (Internet Reliable Transaction Protocol) |
| 29 | ISO-TP4 (ISO Transport Protocol Class 4) |
| 30 | NETBLT (Bulk Data Transfer Protocol) |
| 31 | MFE-NSP (MFE Network Services Protocol) |
| 32 | MERIT-INP (MERIT Internodal Protocol) |
| 33 | DCCP (Datagram Congestion Control Protocol) |
| 34 | 3PC (Third Party Connect Protocol) |
| 35 | IDPR (Inter-Domain Policy Routing Protocol) |
| 36 | XTP |
| 37 | DDP (Datagram Delivery Protocol) |
| 38 | IDPR-CMTP (IDPR Control Message Transport Proto) |
| 39 | TP++ (TP++ Transport Protocol) |
| 40 | IL (IL Transport Protocol) |
| 41 | 6in4 Verkapselung von IPv6- in IPv4-Pakete |
| 42 | SDRP (Source Demand Routing Protocol) |
| 43 | IPv6-Route (Routing Header for IPv6) |
| 44 | IPv6-Frag (Fragment Header for IPv6) |
| 45 | IDRP (Inter-Domain Routing Protocol) |
| 46 | RSVP (Resource Reservation Protocol) |
| 47 | GRE (Generic Routing Encapsulation) |
| 48 | MHRP (Mobile Host Routing Protocol) |
| 49 | BNA |
| 50 | ESP (Encapsulating Security Payload) |
| 51 | AH (Authentication Header) |
| 52 | I-NLSP (Integrated Net Layer Security TUBA) |
| 53 | SWIPE (IP with Encryption) |
| 54 | NARP (NBMA Address Resolution Protocol) |
| 55 | MOBILE (IP Mobility) |
| 56 | TLSP (Transport Layer Security Protocol) |
| 57 | SKIP |
| 58 | IPv6-ICMP (ICMP for IPv6) |
| 59 | IPv6-NoNxt (Kein nächster Header für IPv6) |
| 60 | IPv6-Opts (Destination Options for IPv6) |
| 61 | Jedes Host-interne Protokoll |
| 62 | CFTP |
| 63 | Jedes lokale Netz |
| 64 | SAT-EXPAK (SATNET and Backroom EXPAK) |
| 65 | KRYPTOLAN |
| 66 | RVD (MIT Remote Virtual Disk Protocol) |
| 67 | IPPC (Internet Pluribus Packet Core) |
| 68 | Jedes verteilte Dateisystem |
| 69 | SAT-MON (SATNET Monitoring) |
| 70 | VISA |
| 71 | IPCV (Internet Packet Core Utility) |
| 72 | CPNX (Computer Protocol Network Executive) |
| 73 | CPHB (Computer Protocol Heart Beat) |
| 74 | WSN (Wang Span Network) |
| 75 | PVP (Packet Video Protocol) |
| 76 | BR-SAT-MON (Backroom SATNET Monitoring) |
| 77 | SUN-ND (SUN ND PROTOCOL-Temporary) |
| 78 | WB-MON (WIDEBAND Monitoring) |
| 79 | WB-EXPAK (WIDEBAND EXPAK) |
| 80 | ISO-IP (ISO Internet Protocol) |
| 81 | VMTP |
| 82 | SECURE-VMTP |
| 83 | VINES |
| 84 | TTP |
| 85 | NSFNET-IGP (NSFNET-IGP) |
| 86 | DGP (Dissimilar Gateway Protocol) |
| 87 | TCF |
| 88 | EIGRP (Enhanced Interior Gateway Routing Protocol) |
| 89 | OSPF |
| 90 | Sprite-RPC (Sprite RPC Protocol) |
| 91 | LARP (Locus Address Resolution Protocol) |
| 92 | MTP (Multicast Transport Protocol) |
| 93 | AX.25 (AX.25 Frames) |
| 94 | IPIP (IP-within-IP Encapsulation Protocol) |
| 95 | MICP (Mobile Internetworking Control Pro.) |
| 96 | SCC-SP (Semaphore Communications Sec. Pro.) |
| 97 | ETHERIP (Ethernet-within-IP Encapsulation) |
| 98 | ENCAP (Encapsulation Header) |
| 99 | Jeder private Verschlüsselungsentwurf |
| 100 | GMTP |
| 101 | IFMP (Ipsilon Flow Management Protocol) |
| 102 | PNNI (over IP) |
| 103 | PIM (Protocol Independent Multicast) |
| 104 | ARIS |
| 105 | SCPS |
| 106 | QNX |
| 107 | A/N (Active Networks) |
| 108 | IPComp (IP Payload Compression Protocol) |
| 109 | SNP (Sitara Networks Protocol) |
| 110 | Compaq-Peer (Compaq Peer Protocol) |
| 111 | IPX-in-IP (IPX in IP) |
| 112 | VRRP (Virtual Router Redundancy Protocol) |
| 113 | PGM (PGM Reliable Transport Protocol) |
| 114 | any 0-hop protocol |
| 115 | L2TP (Layer Two Tunneling Protocol) |
| 116 | DDX (D-II Data Exchange (DDX)) |
| 117 | IATP (Interactive Agent Transfer Protocol) |
| 118 | STP (Schedule Transfer Protocol) |
| 119 | SRP (SpectraLink Radio Protocol) |
| 120 | UTI |
| 121 | SMP (Simple Message Protocol) |
| 122 | SM |
| 123 | PTP (Performance Transparency Protocol) |
| 124 | ISIS over IPv4 |
| 125 | FIRE |
| 126 | CRTP (Combat Radio Transport Protocol) |
| 127 | CRUDP (Combat Radio User Datagram) |
| 128 | SSCOPMCE |
| 129 | IPLT |
| 130 | SPS (Secure Packet Shield) |
| 131 | PIPE (Private IP Encapsulation within IP) |
| 132 | SCTP (Stream Control Transmission Protocol) |
| 133 | FC (Fibre Channel) |
| 134 | RSVP-E2E-IGNORE |
| 135 | Mobility Header |
| 136 | UDPLite |
| 137 | MPLS-in-IP |
| 138 | manet (MANET Protocols) |
| 139 | HIP (Host Identity Protocol) |
| 140 | Shim6 (Shim6 Protocol) |
| 141 | WESP (Wrapped Encapsulating Security Payload) |
| 142 | ROHC (Robust Header Compression) |
| 143–252 | Nicht belegt |
| 253–254 | Wird für Experimente und Tests verwendet |
| 255 | Reserviert |