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IP Protocol Numbers

Protocol field values: TCP 6, UDP 17, GRE 47, ESP 50.

#NameDescription
0HOPOPTIPv6 hop-by-hop option
1ICMPInternet Control Message Protocol
2IGMPInternet Group Management Protocol
4IPv4IPv4 encapsulation (IP-in-IP)
6TCPTransmission Control Protocol
17UDPUser Datagram Protocol
41IPv6IPv6 encapsulation (6in4)
46RSVPResource Reservation Protocol
47GREGeneric Routing Encapsulation
50ESPEncapsulating Security Payload (IPsec)
51AHAuthentication Header (IPsec)
58IPv6-ICMPICMPv6
88EIGRPCisco EIGRP
89OSPFOpen Shortest Path First
103PIMProtocol Independent Multicast
112VRRPVirtual Router Redundancy Protocol
115L2TPLayer 2 Tunneling Protocol
124IS-ISIS-IS over IPv4
132SCTPStream Control Transmission Protocol

The value carried in the IPv4 Protocol field and the IPv6 Next Header field. These are not TCP/UDP port numbers: GRE (47), ESP (50) and OSPF (89) ride directly on IP with no ports at all.

About this tool

Free IP protocol numbers reference. A searchable table of IANA IP protocol numbers carried in the IPv4 Protocol and IPv6 Next Header field (TCP, UDP, ICMP, GRE, ESP, AH, OSPF, EIGRP, VRRP, SCTP and more), the values you need for ACLs and firewall rules. Everything runs entirely in your browser — nothing you type is sent to a server.

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