timed(8) System Manager's Manual timed(8)Name
timed - time server daemon
Syntax
/usr/etc/timed [ -i | -n network ][ -E ][ -M ][ -t ]
Description
The daemon synchronizes a host's time with the time of other machines in a local area network running It is normally invoked at boot time
from the file.
Servers running slow down the clocks of some machines and speed up the clocks of others to bring them all to the average network time. The
average network time is computed from measurements of clock differences with the Internet Communication Message Protocol (ICMP) timestamp
request message.
The service provided by is based on a master-slave scheme. When is started on a machine, it asks the master for the network time and sets
the host's clock to that time. After that, it accepts synchronization messages periodically sent by the master and calls the or routine to
perform any corrections on the host's clock.
It also communicates with the command to set the date globally, and with the control program, If the machine running the master crashes,
then the slaves elect a new master from among slaves running with the flag set. The flag provides time synchronization on any attached
networks where no current master server is detected. Such a server propagates the time computed by the top-level master. At least one
daemon on each network must run with the option set to allow it to become a master.
Options-E Overrides the input of slaves. Use the flag in conjunction with the flag. It specifies that a master should not average the times
of the slaves to calculate the network time but should distribute the time of its local host as the network time. This flag allows
a master to distribute time to a network while the network time is controlled by an outside agent such as the Network Time Protocol.
[-i | -n] network
-i Specifies a network to ignore. Each network that appears as an argument to the flag is added to the list of networks that
will ignore. If the flag is used, accesses all networks to which the host is connected except for those networks specified
as arguments to the flag.
-n Specifies a network to use. When the is started, it gathers information about all the network devices connected to the local
host. If neither the flag nor the flag is used, tries to access all the network devices connected to the local host. The
network argument to the flag is the name of a network that should access.
If the switch is used, only those networks specified by the flag are accessed.
Do not use the and flags together.
-M Allows a slave time server to become a master time server if the master server crashes. A system running the daemon without the
flag set remains a slave. The daemon checks for a master time server on each network to which it is connected. It requests syn-
chronization service from the first master server it locates.
-t Enables to trace the messages it receives in the file Tracing can be enabled or disabled with the program.
Restrictions
Any system running with the and options set is eligible to become the master, and distribute its local time to all systems running on its
network. Run the Network Time Protocol daemon, instead of to prevent this behavior.
Files
Invokes the daemon each time the system boots
Tracing file for
Log file for master
See Alsodate(1), adjtime(2), gettimeofday(2), networks(5), ntpd(8), timedc(8)
Introduction to Networking and Distributed System Services
timed(8)