timed(8) System Manager's Manual timed(8)
NAME
timed - The network time daemon
SYNOPSIS
timed [-tME] [-n | -i network]
FLAGS
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 flag is added to the list of networks that the timed daemon will ignore. If the -i flag is used, timed
accesses all networks to which the host is connected except for the specified networks.
If neither the -i flag nor the -n flag is used, timed tries to access all the network devices connected to the local host.
Do not use the -i and -n flags together. Specifies that a machine can become the time server if the master time server becomes
inoperative. See the Restrictions section for more information. Overrides the input of slaves. Use the -E flag in conjunction
with the -M flag. 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 flag 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)). 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 flag is the name of
the network that timed should access. If the -n flag is used, only the specified networks are accessed.
If neither the -n flag nor the -i flag is used, timed tries to access all the network devices connected to the local host.
Do not use the -n and -i flags together. 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 /usr/sbin/timedsetup 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 dae-
mon. 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 periodi-
cally 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 flag 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
flag.
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 host can run the timed with
the -M option.
FILES
Specifies the command path Contains messages traced for the timed command Contains information about the known networks
RELATED INFORMATION
Commands: date(1), timedc(8), timedsetup(8)
Daemons: xntpd(8)
Functions: adjtime(2), gettimeofday(2) delim off
timed(8)