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 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 and lines starting with a hash mark (#) are ignored.
       Remainder of lines are also ignored from the occurrence of
       a hash mark.

       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 net-
       workwide naming service like Yellow Pages/NIS or BIND/Hes-
       oid.

FILES
       /etc/protocols
              The protocols definition file.

SEE ALSO
       getprotoent(3) 

       Guide to Yellow Pages Service

       Guide to BIND/Hesiod Service