redhat 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  pro-
       tocol 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 DDN Network
       Information Center.

       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 networkwide naming 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

Linux								    1995-10-18							      PROTOCOLS(5)