NAME

ntp − query an ntp clock

SYNOPSIS

ntp [  −v  ] [  −s ] [  −f  ] hosts ...

DESCRIPTION

ntp sends an ntp packet to the ntp daemon running on each of the given hosts.  A daemon fills in fields of the ntp packet per RFC1119 and sends the packet back.  ntp then formats and prints the result on the standard output. 

The default output shows the delay, offset, and date in ctime(3C) format.

The following options can reset the time of the local system clock:

−v Verbose output, showing the full contents of received ntp packets, plus caluclated offset, displacement, etc. 

−s Set system time-of-day clock.  Will only happen if time offset is less than compiled-in constant WAYTOBIG (currently 1000 seconds).  Will not happen if remote host is unsynchronized. 

−f Force setting system clock regardless of offset.  Must be used with −s option.  Still will not reset clock if remote system is unsynchronized. 

ntp Results

The default output for each host looks like this:

128.8.10.1: delay:1.845207 offset:-0.358460  Mon Mar 20 08:05:44 1989

The verbose output for each host looks like this:

Packet from: [128.8.10.1]
Leap 0, version 1, mode Server, poll 6, precision -10 stratum 1 (WWVB)
Synch Distance is 0000.1999  0.099991
Synch Dispersion is 0000.0000  0.000000
Reference Timestamp is a7bea6c3.88b40000 Tue Mar  7 14:06:43 1989
Originate Timestamp is a7bea6d7.d7e6e652 Tue Mar  7 14:07:03 1989
Receive Timestamp is   a7bea6d7.cf1a0000 Tue Mar  7 14:07:03 1989
Transmit Timestamp is  a7bea6d8.0ccc0000 Tue Mar  7 14:07:04 1989
Input Timestamp is     a7bea6d8.1a77e5ea Tue Mar  7 14:07:04 1989
umd1: delay:0.019028 offset:-0.043890  Tue Mar  7 14:07:04 1989

The various fields are interpreted as follows:

Packet from: [address]
The address from which this ntp packet was received. 

Leap: n
The leap second indicator.  Nonzero if there is to be a leap second added or subtracted at the new year.

poll = n
The desired poll rate of the peer.

precision = exponent (dec)
The precision of this clock, given in seconds as a power of 2, e.g., a clock derived from the power line frequency (60 Hz) has a precision of 1/6 second (about 2^-6) and would be indicated by a precision of -6.

stratum: n (source)
The stratum of the clock in the ntp hierarchy, along with the source of the clock, either the name of a reference standard (such as WWVB or GOES) or the Internet address of the clock from which this clock is derived. 

Synch Distance is nnn (calculated value). 

Synch Dispersion is nnn (calculated value). 

The next five timestamps are given as ntp fixed-point values, in both hexadecimal and ctime(3C). These are set either by this ntp process or by the server being queried. 

Reference Timestamp is hex-timestamp ctime string
The last time the server clock was adjusted (remote time).

Originate Timestamp is hex-timestamp ctime string
When the ntp request was transmitted by us to the server (local time). 

Receive Timestamp is hex-timestamp ctime string
When the ntp request was received at the server (remote time). 

Transmit Timestamp is hex-timestamp ctime string
When the ntp response was transmitted by the server (remote time). 

Input Timestamp is hex-timestamp ctime string
When the ntp response was received (local time). 

hostname: delay: time offset: time
The summary of the results of the query, giving the host name of the responding clock (from the command line), the round-trip delay, and the offset between the two clocks (assuming symmetric round-trip times).

SEE ALSO

ntpd(1M), ntpdc(1M). 
ctime(3C) in the INTERACTIVE SDS Guide and Programmer’s Reference Manual. RFC1119 Network Time Protocol. 

WARNING

ntp(1M) will only work on INTERACTIVE UNIX System Version 2.3 or later. 

BUGS

Using ntp with the current host will show inaccurate results. 

CREDITS

This facility was developed by the University of Maryland. 

\*U  —  Version 1.0