PROTOCOLS(5)                                                            Linux Programmer's Manual                                                           PROTOCOLS(5)

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⟩

Linux                                                                          2012-08-05                                                                   PROTOCOLS(5)