Hi HP3000-L,

Sorry about my delay in replying to this; I've been rather busy lately!

Donna Garverick wrote:
>
> hi all!
>
> anyone (mark :-) know what all the options are for ntpdate?
> the only thing i can get it to tell me are the available
> options.
>
> :ntpdate.pub.xntp
> usage: NTPDATE.PUB.XNTP [-bBdqsv] [-a key#] [-e delay] [-k
> file]
> [-p samples] [-o version#] [-r rate] [-t timeo] server ...

From the web page that came with the source that I built this version of
ntpdate from:

ntpdate - set the date and time via NTP



Synopsis

ntpdate [ -bBdoqsuv ] [ -a key ] [ -e authdelay ] [ -k
keyfile ] [ -o version ] [ -p samples ] [ -t timeout ]
server [ ... ]

Description

ntpdate sets the local date and time by polling the Network Time
Protocol (NTP) server(s) given as the server arguments to determine the
correct time. It must be run as root on the local host. A number of samples
are obtained from each of the servers specified and a subset of the NTP
clock filter and selection algorithms are applied to select the best of these.
Note that the accuracy and reliability of ntpdate depends on the number
of servers, the number of polls each time it is run and the interval between
runs.

ntpdate can be run manually as necessary to set the host clock, or it can
be run from the host startup script to set the clock at boot time. This is
useful in some cases to set the clock initially before starting the NTP
daemon xntpd. It is also possible to run ntpdate from a cron script.
However, it is important to note that ntpdate with contrived cron scripts
is no substitute for the NTP daemon, which uses sophisticated algorithms to
maximize accuracy and reliability while minimizing resource use. Finally,
since ntpdate does not discipline the host clock frequency as does xntpd,
the accuracy using ntpdate is limited.

Time adjustments are made by ntpdate in one of two ways. If ntpdate
determines the clock is in error more than 0.5 second it will simply step the
time by calling the system settimeofday() routine. If the error is less than
0.5 seconds, it will slew the time by calling the system adjtime() routine.
The latter technique is less disruptive and more accurate when the error is
small, and works quite well when ntpdate is run by cron every hour or
two.

ntpdate will decline to set the date if an NTP server daemon (e.g.,
xntpd) is running on the same host. When running ntpdate on a regular
basis from cron as an alternative to running a daemon, doing so once every
hour or two will result in precise enough timekeeping to avoid stepping the
clock.

Command Line Options

-a key
     Enable the authentication function and specify the key identifier to be
     used for authentication as the argument keyntpdate. The keys and
     key identifiers must match in both the client and server key files. The
     default is to disable the authentication function.

-B
     Force the time to always be slewed using the adjtime() system call,
     even if the measured offset is greater than +-128 ms. The default is
     to step the time using settimeofday() if the offset is greater than
     +-128 ms. Note that, if the offset is much greater than +-128 ms in
     this case, that it can take a long time (hours) to slew the clock to the
     correct value. During this time. the host should not be used to
     synchronize clients.

-b
     Force the time to be stepped using the settimeofday() system call,
     rather than slewed (default) using the adjtime() system call. This
     option should be used when called from a startup file at boot time.

-d
     Enable the debugging mode, in which ntpdate will go through all the
     steps, but not adjust the local clock. Information useful for general
     debugging will also be printed.

-e authdelay
     Specify the processing delay to perform an authentication function as
     the value authdelay, in seconds and fraction (see xntpd for details).
     This number is usually small enough to be negligible for most
     purposes, though specifying a value may improve timekeeping on
     very slow CPU's.

-k keyfile
     Specify the path for the authentication key file as the string keyfile.
     The default is /etc/ntp.keys. This file should be in the format
     described in xntpd.

-o version
     Specify the NTP version for outgoint packets as the integer version,
     which can be 1 or 2. The default is 3. This allows ntpdate to be
     used with older NTP versions.

-p samples
     Specify the number of samples to be acquired from each server as
     the integer samples, with values from 1 to 8 inclusive. The default is
     4.

-q
     Query only - don't set the clock.

-s
     Divert logging output from the standard output (default) to the system
     syslog facility. This is designed primarily for convenience of cron
     scripts.

-t timeout
     Specify the maximum time waiting for a server response as the value
     timeout, in seconds and fraction. The value is is rounded to a
     multiple of 0.2 seconds. The default is 1 second, a value suitable for
     polling across a LAN.

-u
     Direct ntpdate to use an unprivileged port or outgoing packets.
     This is most useful when behind a firewall that blocks incoming traffic
     to privileged ports, and you want to synchronise with hosts beyond
     the firewall. Note that the -d option always uses unprivileged ports.

-v
     Be verbose. This option will cause ntpdate's version identification
     string to be logged.

Files

/etc/ntp.keys - encryption keys used by ntpdate.

Bugs

The slew adjustment is actually 50% larger than the measured offset, since
this (it is argued) will tend to keep a badly drifting clock more accurate.
This is probably not a good idea and may cause a troubling hunt for some
values of the kernel variables tick and tickadj.

David L. Mills ([log in to unmask])