PROTOCOLS(5)		   Linux Programmers 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 proto
       col 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 nam
       ing service like Yellow Pages/NIS or BIND/Hesiod.

FILES
       /etc/protocols
	      The protocols definition file.

SEE ALSO
       getprotoent(3)

       Guide to Yellow Pages Service

       Guide to BIND/Hesiod Service

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

COLOPHON
       This page is part of release 3.05 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				  2002-09-22			  PROTOCOLS(5)