TIMED(8)                                                              TIMED(8)



NAME
       timed - time server daemon

SYNOPSIS
       /etc/timed [ -t ] [ -M ] [ -n network ] [ -i network ]

DESCRIPTION
       _T_i_m_e_d  is  the  time server daemon and is normally invoked at boot time
       from the _r_c(8) file.  It synchronizes the host’s time with the time  of
       other  machines  in  a local area network running _t_i_m_e_d(8).  These time
       servers will slow down the clocks of some machines  and  speed  up  the
       clocks  of others to bring them to the average network time.  The aver‐
       age network time is computed from  measurements  of  clock  differences
       using the ICMP timestamp request message.

       The service provided by _t_i_m_e_d is based  on a master-slave scheme.  When
       _t_i_m_e_d(8) 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 _a_d_j_‐
       _t_i_m_e(2) to perform the needed corrections on the host’s clock.

       It  also  communicates  with _d_a_t_e(1) in order to set the date globally,
       and with _t_i_m_e_d_c(8), a timed control program.  If  the  machine  running
       the  master crashes, then the slaves will elect a new master from among
       slaves running with the -M flag.  A _t_i_m_e_d running without the  -M  flag
       will  remain  a slave.  The -t flag enables _t_i_m_e_d to trace the messages
       it receives in the file /usr/adm/timed.log.  Tracing can be  turned  on
       or  off  by  the program _t_i_m_e_d_c(8).  _T_i_m_e_d normally checks for a master
       time server on each network to which it is connected, except  as  modi‐
       fied  by  the options described below.  It will request synchronization
       service from the first master server located.  If permitted by  the  -M
       flag,  it will provide synchronization service on any attached networks
       on which no current master server was detected.  Such a  server  propa‐
       gates the time computed by the top-level master.  The -n flag, followed
       by the name of a network which the  host  is  connected  to  (see  _n_e_t_‐
       _w_o_r_k_s(5)),  overrides  the default choice of the network addresses made
       by the program.  Each time the -n flag appears, that  network  name  is
       added  to  a  list  of valid networks.  All other networks are ignored.
       The -i flag, followed by the name of a network to  which  the  host  is
       connected  (see  _n_e_t_w_o_r_k_s(5)), overrides the default choice of the net‐
       work addresses made by the program.  Each time  the  -i  flag  appears,
       that  network name is added to a list of networks to ignore.  All other
       networks are used by the time daemon.  The -n and -i flags are meaning‐
       less if used together.

FILES
       /usr/adm/timed.log           tracing file for timed
       /usr/adm/timed.masterlog     log file for master timed

SEE ALSO
       date(1), adjtime(2), gettimeofday(2), icmp(4P), timedc(8),
       _T_S_P_:  _T_h_e _T_i_m_e _S_y_n_c_h_r_o_n_i_z_a_t_i_o_n _P_r_o_t_o_c_o_l _f_o_r _U_N_I_X _4_._3_B_S_D, R. Gusella and
       S. Zatti



4.3 Berkeley Distribution        May 28, 1986                         TIMED(8)