List of IP protocol numbers

Below are the Assigned Internet Protocol Numbers found in the Protocol field of the IPv4 header and the Next Header field of the IPv6 header. The same values are used in both versions of the field and define the layout of the header that will immediately follow the IPv4 or IPv6 header. Both the Protocol and Next Header fields are eight bits wide. The Protocol Numbers are managed and assigned by the Internet Assigned Numbers Authority (IANA).