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(libc.info)Configuring Inetd

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Configuring `inetd'
-------------------

   The file `/etc/inetd.conf' tells `inetd' which ports to listen to
and what server programs to run for them.  Normally each entry in the
file is one line, but you can split it onto multiple lines provided all
but the first line of the entry start with whitespace.  Lines that
start with `#' are comments.

   Here are two standard entries in `/etc/inetd.conf':

     ftp	stream	tcp	nowait	root	/libexec/ftpd	ftpd
     talk	dgram	udp	wait	root	/libexec/talkd	talkd

   An entry has this format:

     SERVICE STYLE PROTOCOL WAIT USERNAME PROGRAM ARGUMENTS

   The SERVICE field says which service this program provides.  It
should be the name of a service defined in `/etc/services'.  `inetd'
uses SERVICE to decide which port to listen on for this entry.

   The fields STYLE and PROTOCOL specify the communication style and
the protocol to use for the listening socket.  The style should be the
name of a communication style, converted to lower case and with `SOCK_'
deleted--for example, `stream' or `dgram'.  PROTOCOL should be one of
the protocols listed in `/etc/protocols'.  The typical protocol names
are `tcp' for byte stream connections and `udp' for unreliable
datagrams.

   The WAIT field should be either `wait' or `nowait'.  Use `wait' if
STYLE is a connectionless style and the server, once started, handles
multiple requests as they come in.  Use `nowait' if `inetd' should
start a new process for each message or request that comes in.  If
STYLE uses connections, then WAIT *must* be `nowait'.

   USER is the user name that the server should run as.  `inetd' runs
as root, so it can set the user ID of its children arbitrarily.  It's
best to avoid using `root' for USER if you can; but some servers, such
as Telnet and FTP, read a username and password themselves.  These
servers need to be root initially so they can log in as commanded by
the data coming over the network.

   PROGRAM together with ARGUMENTS specifies the command to run to
start the server.  PROGRAM should be an absolute file name specifying
the executable file to run.  ARGUMENTS consists of any number of
whitespace-separated words, which become the command-line arguments of
PROGRAM.  The first word in ARGUMENTS is argument zero, which should by
convention be the program name itself (sans directories).

   If you edit `/etc/inetd.conf', you can tell `inetd' to reread the
file and obey its new contents by sending the `inetd' process the
`SIGHUP' signal.  You'll have to use `ps' to determine the process ID
of the `inetd' process as it is not fixed.