INETD(8,C) AIX TCP/IP User's Guide INETD(8,C)
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inetd
PURPOSE
Provides inetd socket management.
SYNTAX
+------+ +---------------+
/etc/inetd ---| |---| |---|
+- -d -+ +- config_file -+
DESCRIPTION
The inetd command should be run at boot time by /etc/rc.tcpip. It then listens
for connections on certain Internet sockets. When a connection is found on one
of its sockets, it decides what service the socket corresponds to and invokes a
program to service the request. After the program is finished, it continues to
listen on the socket. Essentially, inetd is a master daemon which invokes
service daemons as needed, thus reducing the system load.
There must be an entry for each field of the configuration file, with entries
for each field separated by a tab or a space. Comments are denoted by a "#" at
the beginning of a line. The fields of the configuration file are as follows:
service name
socket type
protocol
wait/nowait
user
server program
server program arguments
The service name entry is the name of the valid service in the file
/etc/services/. For internal services (discussed below), the service name must
be the official name of the service (that is, the first entry in
/etc/services).
The socket type should be of stream, dgram, raw, rdm, or seqpacket depending on
whether the socket is a stream, datagram, raw, reliably delivered message, or
sequenced packet socket.
The protocol must be a valid protocol as given in /etc/protocols. Examples
might be tcp or udp.
The wait/nowait entry is applicable to datagram sockets only (other sockets
should have a nowait entry in this space). If a datagram server connects to
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INETD(8,C) AIX TCP/IP User's Guide INETD(8,C)
its peer, freeing the socket so inetd can receive further messages on the
socket, it is said to be multi-threaded server, and should use the nowait
entry. For datagram servers which process all incoming datagrams on a socket
and eventually time out, the server is said to be single-threaded and should
use the wait entry. Comsat (biff) and talk are both examples of the latter
type of datagram server. Tftpd is an exception; it is a datagram server that
establishes pseudo-connections.
It must be listed as wait in order to avoid a race; the server reads the first
packet, creates a new socket, and then forks and exits to allow inetd to check
for new service requests to spawn new servers.
The user entry should contain the user name of the user as whom the server
should run. This allows for servers to be given less permission than root.
The server program entry should contain the path name of the program which is
to be executed by inetd when a request is found on its socket. If inetd
provides this service internally, this entry should be internal.
The arguments to the server program should be just as they normally are,
starting with argv[0], which is the name of the program. If the service is
provided internally, the work internal should take the place of this entry.
The inetd command provides several trivial services internally by use of
routines within itself. These services are echo, discard, chargen (character
generator), daytime (human readable time), and time (machine readable time, in
the form of the number of seconds since midnight, January 1, 1900). All of
these services are TCP based.
The inetd command rereads its configuration file when it receives a hangup
signal, SIGHUP. Services may be added, deleted or modified when the
configuration file is reread.
FLAGS
-d Causes debugging information to be printed, in a single self-explanatory
format, on inetd's standard error output each time the daemon services a
request from the network.
RELATED INFORMATION
In this book:
"inetd.conf"
"ftpd"
"lpd"
"rexecd"
"telnetd"
"tftpd"
"talkd"
"rshd"
"rlogind"
"fingerd"
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