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 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)

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

COLOPHON
       This  page  is  part of release 4.10 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest	  version     of     this    page,    can    be	   found    at
       https://www.kernel.org/doc/man-pages/.



Linux				  2012-08-05			  PROTOCOLS(5)