inetd(1M)
NAME
inetd - Internet services daemon
SYNOPSIS
inetd [-d] [-s] [-t] [ -r count interval] [configuration-
file]
DESCRIPTION
inetd is the server process for the Internet standard ser-
vices. It usually starts up at system boot time. The
configuration-file lists the services that inetd is to pro-
vide. If no configuration-file is given on the command line,
inetd reads the configuration information from the
/etc/inetd.conf file. If /etc/inetd.conf is not present,
inetd reads the configuration information from
/etc/inet/inetd.conf. See inetd.conf(4) for more information
on the format of this file.
inetd listens for service requests on the TCP or UDP ports
associated with each of the services listed in the confi-
guration file. When a request arrives, inetd executes the
server program associated with the service.
A service can be configured to have "wait" wait-status, in
which case, inetd waits for the server process to exit
before starting a second server process. RPC services can
also be started by inetd.
inetd provides a number of simple Internet services inter-
nally. These include echo, discard, chargen (character gen-
erator), daytime (human-readable time), and time (machine-
readable time, in the form of the number of seconds since
midnight, January 1, 1900).
inetd reads the configuration-file and the default settings
in /etc/default/inetd once when it starts up and rereads
them again whenever it receives a hangup signal, SIGHUP. New
services can be activated and existing services can be
deleted or modified by editing the configuration-file and
then sending inetd a SIGHUP signal.
After it receives the SIGHUP signal, inetd reads the
configuration-file and, for each service listed, attempts to
bind() to that service's port. The attempt might fail if
another standalone server or "wait" wait-status server
started by inetd is already listening on the same port. Such
a server has to be killed before inetd can bind to the
service's port. inetd defers implementing a newly read con-
figuration for a service whose port is busy and periodically
attempts to start listening, after logging an error on con-
sole. The retry interval is currently 10 minutes.
If you want a "wait" wait-status server that is started by
in etd to be controlled by that daemon following a kill and
restart of inetd, you must do one of the following:
o Kill the server before restarting inetd.
o Restart inetd, kill the server, and wait till the
retry interval elapses. After this time, inetd
attempts to restart the server upon the next request
for service.
The /etc/default/inetd file contains the following default
parameter settings. See FILES.
ENABLE_CONNECTION_LOGGING
Specifies whether incoming TCP connections are traced.
The value ENABLE_CONNECTION_LOGGING=YES is equivalent
to the -t command-line option. The default value for
ENABLE_CONNECTION_LOGGING is NO.
ENABLE_TCPWRAPPERS
Specifies the TCP wrappers facility will be used to
control access to TCP services. The value YES enables
checking. The default value for ENABLE_TCPWRAPPERS is
NO. If the ENABLE_TCPWRAPPERS parameter is turned on,
then all "streams, nowait" services will be automati-
cally wrapped by the TCP wrappers facility. The syslog
facility code daemon is used to log allowed connec-
tions (using the notice severity level) and denied
traffic (using the warning severity level). See
syslog.conf(4) for a description of syslog codes and
severity levels. The stability level of the TCP
wrappers facility and its configuration files is
External. As the TCP wrappers facility is not con-
trolled by Sun, intrarelease incompatibilities are not
uncommon. See attributes(5).
For more information about configuring TCP wrappers, you can
refer to the following man pages, which are delivered as
part of Solaris at /usr/sfw/man: tcpd(1M), hosts_access(4).
OPTIONS
-d Runs inetd in the foreground and enables debugging
output.
-s Allows you to run inetd ``stand-alone'' outside the
Service Access Facility (SAF). If the -s option is
omitted, inetd will attempt to contact the service
access controller (SAC) and will exit if SAC is not
already running. See sac(1M).
-t Instructs inetd to trace the incoming connections for
all of its TCP services. It does this by logging the
client's IP address and TCP port number, along with
the name of the service, using the syslog(3C) facil-
ity. "Wait" wait-status services cannot be traced.
When tracing is enabled, inetd uses the syslog facil-
ity code daemon and notice priority level. This log-
ging is separate from the logging done by the TCP
wrappers facility. See FILES.
-r Allows inetd to detect and then suspend ``broken''
wait services servers and connectionless datagram ser-
vices servers, for example, UDP and RPC/CLTS. Without
this detection, a buggy server that fails before con-
suming the service request is continuously restarted
and taxes system resources too much. The -r flag has
the form:
-r count interval
count and interval are decimal numbers that represent
the maximum count of invocations per interval of
seconds a service can be started before the service is
considered ``broken.''
After being considered ``broken,'' a server is
suspended for ten minutes. After ten minutes, inetd
again enables service, trusting the server to operate
correctly.
If the -r flag is not specified, inetd considers -r40
60 to be specified.
OPERANDS
configuration-file
Lists the services inetd is to provide.
EXIT STATUS
inetd does not return an exit status.
FILES
/etc/default/inetd
Contains default settings. inetd reads the
configuration-file and the default settings in
/etc/default/inetd once when it starts up and rereads
them again whenever it receives a hangup signal,
SIGHUP. You can override some of the settings by
command-line options.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
SEE ALSO
in.ftpd(1M), in.rexecd(1M), in.rshd(1M), in.tftpd(1M),
sac(1M), syslog(3C), inetd.conf(4), syslog.conf(4), attri-
butes(5)
Postel, Jon. RFC 862: Echo Protocol. Network Information
Center, SRI International, Menlo Park, CA, May 1983.
Postel, Jon. RFC 863: Discard Protocol. Network Information
Center, SRI International, Menlo Park, CA, May 1983.
Postel, Jon. RFC 864: Character Generator Protocol. Network
Information Center, SRI International, Menlo Park, CA, May
1983.
Postel, Jon. RFC 867: Daytime Protocol. Network Information
Center, SRI International, Menlo Park, CA, May 1983.
Postel, Jon, and Ken Harrenstien. RFC 868: Time Protocol.
Network Information Center, SRI International, Menlo Park,
CA, May 1983.
The following man pages are delivered as part of the
SUNWtcpd package: tcpd(1M), hosts_access(4)
WARNINGS
Do not configure udp services as nowait. This can cause a
race condition where the inetd program selects on the socket
and the server program reads from the socket. Many server
programs will fork and performance will be severely comprom-
ised.
If you kill and restart inetd, be aware that any environment
variables in your shell are inherited by a shell for an
incoming telnet session. For example, if you have USER=root
in your environment, a user who connects to your machine
with telnet inherits USER=root.
NOTES
For RPC services, inetd listens on all the transports, not
only tcp and udp, as specified for each service in the
inetd.conf(4) file.
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