<font size=2 face="sans-serif"> I'll
try and dig into this further, but our Citrix environment had a similar
problem. It was that the UID after boot(Windows) was not the same
as the UID during the PIX boot. The MAC's were the same but because
the UID was different, 2 different IP's were given out.<br>
<br>
This was the solution if I remember correctly.<br>
<br>
<br>
</font><tt><font size=1>Add ignore-client-uids option in the server. This
option causes<br>
the server to not record a client's uid in its lease. This<br>
violates the specification but may also be useful when a client<br>
can dual boot using different client ids but the same mac address.<br>
</font></tt>
<br>
<br>
<br>
<br><font size=5 color=blue><b>David A. Evans</b></font>
<br><font size=3><b>Enterprise IP/DNS Management</b></font>
<br><font size=3><b>Network Infrastructure Tools and Services</b></font>
<br><a href=mailto:Evans_David_A@cat.com><font size=3 color=blue><b><u>Evans_David_A@cat.com</u></b></font></a>
<br>
<br>
<br>
<br><font size=1 color=#5f5f5f face="sans-serif">From:
</font><font size=1 face="sans-serif">Stephen Borrill <dhcp-users@borrill.org.uk></font>
<br><font size=1 color=#5f5f5f face="sans-serif">To:
</font><font size=1 face="sans-serif">dhcp-users@lists.isc.org</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Date:
</font><font size=1 face="sans-serif">10/21/2014 10:02 AM</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Subject:
</font><font size=1 face="sans-serif">Re: 2 IP addresses
when PXE booting, ping check doesn't spot same MAC
address</font>
<br><font size=1 color=#5f5f5f face="sans-serif">Sent by:
</font><font size=1 face="sans-serif">dhcp-users-bounces@lists.isc.org</font>
<br>
<hr noshade>
<br>
<br>
<br><tt><font size=2>On 21/10/2014 14:12, Patrick Trapp wrote:<br>
>> I'm using a diskless system to boot Windows (Citrix Provisioning
<br>
>> Services). This does a BIOS PXE boot, loads a bootstrap file from
<br>
>> TFTP which connects to a virtual hard disk and then continues
with <br>
>> the Windows boot as though it were a local disk. This means that
the <br>
>> IP address acquired from the BIOS is inherited by Windows and<br>
>> remains in use. The interface within Windows is still set up to
use<br>
>> DHCP and so it goes through its usual DHCP phase.<br>
>> <br>
>> It is common to end up with 2 IP addresses on the network when
doing<br>
>> this. Initially the problem was that the BIOS does not send
a UID <br>
>> with the request, but Windows does, so that dhcpd was treating
them <br>
>> as two separate leases. I upgraded to v4.3.0 and used <br>
>> "ignore-client-uids true" to stop this. However, this
then triggered <br>
>> another problem. At the time that Windows requests its IP address,
<br>
>> the IP address from the PXE phase is still active as it cannot
be <br>
>> released by the client. Therefore, the dhcpd ping check triggers,<br>
>> the original IP address is abandoned and a new IP address is picked:<br>
>> <br>
[snip]<br>
>> To test this theory, setting "ping-check false" allows
the machine to<br>
>> keep its single initial address.<br>
>> <br>
>> It seems to me that there should be an option to only abandon
an IP <br>
>> address after a ping check if the MAC address that responds does
not<br>
>> match the requester. Any other suggestions?<br>
><br>
> Perhaps I miss the point of the request, but I think we have a system<br>
> that does something similar (as far as a two-stage boot). The first<br>
> stage gets a very short lease (I'm not sure how) - is there a client<br>
> option that would override (underride?) the server's default minimum<br>
> lease time that you could utilize?<br>
<br>
Problem is that the first stage boot is not just a transitory bootstrap,<br>
it is effectively providing a permanent link to the virtual disk, so the<br>
IP address cannot be released. The usual PXEClient class to modify the<br>
lease time therefore would not help.<br>
<br>
-- <br>
Stephen<br>
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