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timed(8)
NAME
timed - The network time daemon
SYNOPSIS
timed [-tME] [-n | -i network]
OPTIONS
-i network
Specifies the names of the networks (as defined in the /etc/networks
file) to be excluded from clock synchronization. Each network name that
is an argument to the -i option is added to the list of networks that
the timed daemon will ignore. If the -i option is used, timed accesses
all networks to which the host is connected except for the specified
networks.
If neither the -i option nor the -n option is used, timed tries to
access all the network devices connected to the local host.
Do not use the -i and -n options together.
-M Specifies that a machine can become the time server if the master time
server becomes inoperative. See RESTRICTIONS for more information.
-E Overrides the input of slaves. Use the -E option in conjunction with
the -M option. It specifies that a master timed system will not
average the times of the slaves to calculate the network time.
Instead, it distributes the time of its local host as the network time.
This option allows a master timed system to distribute time to a
network while the network time is controlled by an outside agent (such
as the Network Time Protocol (NTP)).
-n network
Specifies the names of the networks (as defined in the /etc/networks
file) to be included in clock synchronization. When timed is started,
it gathers information about all the network devices connected to the
local host. The network argument to the -n option is the name of the
network that timed should access. If the -n option is used, only the
specified networks are accessed.
If neither the -n option nor the -i option is used, timed tries to
access all the network devices connected to the local host.
Do not use the -n and -i options together.
-t Enables tracing of messages received in /usr/adm/timed.log.
DESCRIPTION
The timed daemon is not invoked at boot time by default. You can use the
/usr/sbin/timedsetup utility to configure the timed daemon.
The timed daemon synchronizes the host's clock with those of other machines
on the local area network that are also running the timed daemon. The timed
daemon slows the clocks of some machines and speeds up the clocks on other
machines to create an average network time. The average network time is
computed from measurements of clock differences using the Internet Control
Message Protocol (ICMP) timestamp request message.
The service provided by timed is based on a master/slave (client/server)
scheme. When timed is started on a machine, it asks the master timed
daemon for the network time and sets the host's clock to that time. After
that, the host accepts synchronization messages periodically sent by the
master and calls the adjtime() system call to perform the needed
corrections on the host's clock.
The timed daemon also communicates with the date command to set the date
globally, and with timedc, the timed control program.
If the machine running the master ceases to function, a machine that is
running the timed daemon with the -M option becomes the new master timed
daemon.
Note
The timed daemon is provided for compatibility. Tru64 UNIX also
provides support for the Network Time Protocol through the xntpd
daemon. You should use NTP for time synchronization. If you need to
run both NTP and the timed daemon, you must run the timed daemon with
the -E option.
If you plan to run both the timed daemon and NTP, you should also
configure NTP first.
RESTRICTIONS
In configurations with two or more hosts each connected to the same two or
more subnetworks, only one of the hosts can run the timed daemon by using
the -M option.
FILES
/usr/sbin/timed
Specifies the command path.
/var/adm/timed.log
Contains messages traced for the timed command.
/etc/networks
Contains information about the known networks.
SEE ALSO
Commands: date(1), timedc(8), timedsetup(8)
Daemons: xntpd(8)
Functions: adjtime(2), gettimeofday(2)
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