NAME

       protocols - protocols definition file

DESCRIPTION

       This  file is a plain ASCII file, describing the various DARPA internet protocols that are
       available from the TCP/IP subsystem.  It should be consulted instead of using the  numbers
       in  the  ARPA include files, or, even worse, just guessing them.  These numbers will occur
       in the protocol field of any IP header.

       Keep this file untouched since changes would result in incorrect  IP  packages.   Protocol
       numbers and names are specified by the IANA (Internet Assigned Numbers Authority).

       Each line is of the following format:

              protocol number aliases ...

       where  the  fields  are  delimited by spaces or tabs.  Empty lines are ignored.  If a line
       contains a hash mark (#), the hash mark and the part of the line following it are ignored.

       The field descriptions are:

       protocol
              the native name for the protocol.  For example ip, tcp, or udp.

       number the official number for this protocol as it will appear within the IP header.

       aliases
              optional aliases for the protocol.

       This file might be distributed over a network using a  network-wide  naming  service  like
       Yellow Pages/NIS or BIND/Hesiod.

FILES

       /etc/protocols
              The protocols definition file.

SEE ALSO

       getprotoent(3)

       ⟨http://www.iana.org/assignments/protocol-numbers⟩