<div dir="ltr"><div dir="ltr"><div dir="ltr"><div>The times in the DHCP packets should all be relative, so it should not matter if the client and server clocks differ.</div><div><br></div><div dir="ltr"><a href="https://tools.ietf.org/html/rfc2131#section-3.3">https://tools.ietf.org/html/rfc2131#section-3.3</a></div><div dir="ltr">"   As clients and servers may not have synchronized clocks, times are<div dir="ltr">   represented in DHCP messages as relative times, to be interpreted</div><div dir="ltr">   with respect to the client's local clock."</div><div><div dir="ltr" class="gmail_signature"><br>-- <br>Bob Harold<br><br></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, May 6, 2019 at 12:54 PM Sten Carlsen <<a href="mailto:stenc@s-carlsen.dk">stenc@s-carlsen.dk</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
  
    
  
  <div bgcolor="#FFFFCC">
    <br>
    <br>
    <div class="gmail-m_2381733553852072717moz-cite-prefix">On 06/05/2019 18.06, Murali Krishna
      wrote:<br>
    </div>
    <blockquote type="cite">
      
      <div dir="ltr">
        <div>Hi Carlsen,</div>
        <div><br>
        </div>
        <div>Time on the client side was not observed. Will try to get
          the time on server and the client when this is observed.</div>
        <div>Is this the expected behaviour of the dhcp that the server
          hands out a lease covering the time from the clients time to
          the current server time?</div>
      </div>
    </blockquote>
    I don't know. IIRC time from both ends is in the packets.<br>
    <br>
    I am sure someone else knows how the time is actually calculated, I
    was mostly guessing.<br>
    <br>
    Sten<br>
    <blockquote type="cite">
      <div dir="ltr">
        <div><br>
        </div>
        Thanks & Regards,
        <div>Muralikrishna CH<br>
          <div class="gmail_quote">
            <div dir="ltr" class="gmail_attr">On Mon, May 6, 2019 at
              9:07 PM Sten Carlsen <<a href="mailto:stenc@s-carlsen.dk" target="_blank">stenc@s-carlsen.dk</a>>
              wrote:<br>
            </div>
            <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
              <div bgcolor="#FFFFCC"> Interesting.<br>
                <br>
                Seems the server hands out a lease covering the time
                from the client's time to the current server time,
                essentially forever.<br>
                <br>
                This might have been done to compensate for the elapsed
                time from the client sends the request until it is
                handled.<br>
                <br>
                One might think a cap on that time gap would be
                appropriate.<br>
                <br>
                I wonder if the client was ahead of the server time
                wise, would the lease then be shorter -> negative
                -> no lease time?<br>
                <br>
                <div class="gmail-m_2381733553852072717gmail-m_-8392774289414875111moz-cite-prefix">On
                  06/05/2019 16.54, Murali Krishna wrote:<br>
                </div>
                <blockquote type="cite">
                  <div dir="ltr">Hi,
                    <div><br>
                    </div>
                    <div>Before we tried to collect the packet captures.
                      I would like to share some information on the
                      issue.</div>
                    <div>While analyzing the logs, it has been observed
                      that the system time is updated to very old time
                      stamp(almost 5yrs back). From this point onwards
                      we are able to see that the huge lease value is
                      getting updated in the client lease file. <br>
                    </div>
                    <div>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>30566:Tue Apr 30 14:58:03 IST 2019</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>30804:Tue Apr 30 14:58:24 IST 2019</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>31042:Fri May  2 00:00:14 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>31280:Fri May  2 00:00:35 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>31531:Fri May  2 00:00:56 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>…</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>33379:Fri May  2 00:03:23 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>33643:Fri May  2 00:03:44 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>33907:Fri May  2 00:04:05 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>34171:Fri May  2 00:04:26 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>34435:Fri May  2 00:04:47 IST 2014</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>34699:Tue Apr 30 15:03:39 IST 2019</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt;font-family:Calibri,sans-serif"><span>34963:Tue Apr 30 15:04:00 IST 2019</span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt;font-size:11pt"><span style="font-size:9pt"><font face="arial,
                            helvetica, sans-serif"><br>
                          </font></span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt"><span style="font-size:12px"><font face="arial, helvetica, sans-serif">Even
                            though the system time is updated to the
                            current time, there was no update to the
                            client lease file.  client lease file is
                            updated to the correct value only after we
                            restarted the client.</font></span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt"><span style="font-size:12px"><font face="arial, helvetica, sans-serif"><br>
                          </font></span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt"><span style="font-size:12px"><font face="arial, helvetica, sans-serif">Thanks
                            & Regards,</font></span></p>
                      <p class="MsoNormal" style="margin:0cm 0cm 0.0001pt"><span style="font-size:12px"><font face="arial, helvetica, sans-serif">Muralikrishna
                            CH</font></span></p>
                    </div>
                  </div>
                  <br>
                  <div class="gmail_quote">
                    <div dir="ltr" class="gmail_attr">On Tue, Apr 16,
                      2019 at 10:32 PM Simon Hobson <<a href="mailto:dhcp1@thehobsons.co.uk" target="_blank">dhcp1@thehobsons.co.uk</a>>
                      wrote:<br>
                    </div>
                    <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Sten Carlsen
                      <<a href="mailto:stenc@s-carlsen.dk" target="_blank">stenc@s-carlsen.dk</a>>
                      wrote:<br>
                      <br>
                      > The server is configured with two times,
                      max-lease-time and default-lease-time.<br>
                      <br>
                      Just to expend on that ...<br>
                      There is also min-lease-time.<br>
                      <br>
                      If the client specifies a desired lease time then
                      the server will give that subject to min and max
                      lease times.<br>
                      If the client does not ask for a specific lease
                      time, then the default lease time is offered.<br>
                      <br>
                      As already mentioned, the first thing to do is
                      look more closely at your packet captures. Check
                      which devices the packets come from, and what's in
                      them - particularly what options the client sends.<br>
                      <br></blockquote></div>
                  -- <div dir="ltr" class="gmail-m_2381733553852072717gmail-m_-8392774289414875111gmail_signature"><div dir="ltr"><div>
                        <br>
                        Thanks & Regards,<br>
                        Muralikrishna CH</div></div></div></blockquote></div></blockquote></div><div dir="ltr" class="gmail-m_2381733553852072717gmail_signature"><div dir="ltr"><div>
                <br>
                Thanks & Regards,<br>
                Muralikrishna CH<br></div></div></div></div></div></blockquote></div>
</blockquote></div></div></div></div>