linux man page for protocols

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

NAME
       protocols - the 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 (Inter-
       net 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

COLOPHON
       This  page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2008-09-23							      PROTOCOLS(5)