459 lines
7.4 KiB
HTML
459 lines
7.4 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>NTP Toolkit</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="Linux System Administrators Guide"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Keeping Time"
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HREF="keeping-time.html"><LINK
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REL="PREVIOUS"
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TITLE="Basic NTP configuration"
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HREF="basic-ntp-config.html"><LINK
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REL="NEXT"
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TITLE="Some known NTP servers"
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HREF="ntp-servers.html"></HEAD
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><BODY
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CLASS="SECT1"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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SUMMARY="Header navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>Linux System Administrators Guide: </TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="basic-ntp-config.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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>Chapter 14. Keeping Time</TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="ntp-servers.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="SECT1"
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><H1
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CLASS="SECT1"
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><A
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NAME="NTP-TOOLKIT"
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></A
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>14.7. NTP Toolkit</H1
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><P
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>There are a number of utilities available to check if
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NTP is doing it's job. The <B
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CLASS="COMMAND"
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>ntpq -p</B
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> command
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will print out your system's current time status.
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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><TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ntpq -p</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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> remote refid st t when poll reach delay offset jitter
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==============================================================================
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*cudns.cit.corne ntp0.usno.navy. 2 u 832 1024 377 43.208 0.361 2.646
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LOCAL(0) LOCAL(0) 10 l 13 64 377 0.000 0.000 0.008</TT
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></PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> The <B
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CLASS="COMMAND"
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>ntpdc -c loopinfo</B
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> will display
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how far off the system time is in seconds, based upon the last time
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the remote server was contacted.
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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><TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ntpdc -c loopinfo</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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>offset: -0.004479 s
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frequency: 133.625 ppm
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poll adjust: 30
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watchdog timer: 404 s</TT
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>
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</PRE
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></FONT
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></TD
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></TR
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></TABLE
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></P
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><P
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><B
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CLASS="COMMAND"
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>ntpdc -c kerninfo</B
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> will display
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the current remaining correction.
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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><TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ntpdc -c kerninfo</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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>pll offset: -0.003917 s
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pll frequency: 133.625 ppm
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maximum error: 0.391414 s
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estimated error: 0.003676 s
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status: 0001 pll
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pll time constant: 6
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precision: 1e-06 s
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frequency tolerance: 512 ppm
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pps frequency: 0.000 ppm
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pps stability: 512.000 ppm
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pps jitter: 0.0002 s
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calibration interval: 4 s
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calibration cycles: 0
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jitter exceeded: 0
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stability exceeded: 0
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calibration errors: 0</TT
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>
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</PRE
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></FONT
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></TD
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></TR
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></TABLE
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></P
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><P
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> A slightly more different version of
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<B
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CLASS="COMMAND"
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>ntpdc -c kerninfo</B
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> is <B
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CLASS="COMMAND"
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>ntptime</B
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>
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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><TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ntptime</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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>ntp_gettime() returns code 0 (OK)
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time c35e2cc7.879ba000 Thu, Nov 13 2003 11:16:07.529, (.529718),
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maximum error 425206 us, estimated error 3676 us
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ntp_adjtime() returns code 0 (OK)
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modes 0x0 (),
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offset -3854.000 us, frequency 133.625 ppm, interval 4 s,
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maximum error 425206 us, estimated error 3676 us,
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status 0x1 (PLL),
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time constant 6, precision 1.000 us, tolerance 512 ppm,
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pps frequency 0.000 ppm, stability 512.000 ppm, jitter 200.000 us,
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intervals 0, jitter exceeded 0, stability exceeded 0, errors 0.</TT
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></PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> Yet another way to see how well NTP is working is
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with the <B
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CLASS="COMMAND"
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>ntpdate -d</B
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> command. This will
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contact an NTP server and determine the time difference
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but not change your system's time.
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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><TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ntpdate -d 132.236.56.250</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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>13 Nov 14:43:17 ntpdate[29631]: ntpdate 4.1.1c-rc1@1.836 Thu Feb 13 12:17:20 EST 2003 (1)
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transmit(132.236.56.250)
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receive(132.236.56.250)
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transmit(132.236.56.250)
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receive(132.236.56.250)
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transmit(132.236.56.250)
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receive(132.236.56.250)
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transmit(132.236.56.250)
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receive(132.236.56.250)
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transmit(132.236.56.250)
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server 132.236.56.250, port 123
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stratum 2, precision -17, leap 00, trust 000
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refid [192.5.41.209], delay 0.06372, dispersion 0.00044
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transmitted 4, in filter 4
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reference time: c35e5998.4a46cfc8 Thu, Nov 13 2003 14:27:20.290
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originate timestamp: c35e5d55.d69a6f82 Thu, Nov 13 2003 14:43:17.838
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transmit timestamp: c35e5d55.d16fc9bc Thu, Nov 13 2003 14:43:17.818
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filter delay: 0.06522 0.06372 0.06442 0.06442
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0.00000 0.00000 0.00000 0.00000
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filter offset: 0.000036 0.001020 0.000527 0.000684
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0.000000 0.000000 0.000000 0.000000
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delay 0.06372, dispersion 0.00044
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offset 0.001020
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13 Nov 14:43:17 ntpdate[29631]: adjust time server 132.236.56.250 offset 0.001020 sec</TT
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></PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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> If you want actually watch the system
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synchronize you can use <B
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CLASS="COMMAND"
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>ntptrace</B
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>.
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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><TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ntptrace 132.236.56.250</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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>cudns.cit.cornell.edu: stratum 2, offset -0.003278, synch distance 0.02779
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truetime.ntp.com: stratum 1, offset -0.014363, synch distance 0.00000, refid 'ACTS'</TT
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></PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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</P
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><P
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>If you need your system time synchronized immediately
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you can use the <B
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CLASS="COMMAND"
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>ntpdate remote-servername</B
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>
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to force a synchronization. No waiting!
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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><TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ntpdate 132.236.56.250</B
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></TT
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>
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13 Nov 14:56:28 ntpdate[29676]: adjust time server 132.236.56.250 offset -0.003151 sec
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<TT
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CLASS="COMPUTEROUTPUT"
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></TT
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></PRE
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></FONT
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></TD
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></TR
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></TABLE
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></P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="basic-ntp-config.html"
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ACCESSKEY="P"
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>Prev</A
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</A
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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HREF="ntp-servers.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Basic NTP configuration</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="keeping-time.html"
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ACCESSKEY="U"
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>Up</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Some known NTP servers</TD
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></TR
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></TABLE
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></DIV
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></BODY
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