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<div dir="ltr"><font color="#000000" size="2" face="Tahoma">We have proprietary network devices that use rely on DHCP for configuration. We're using a standard 72 hour lease time, and we rely on the IPs to not change, so long as these devices aren't offline
for much more than a reboot.</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">Static assignments by MAC address are not feesible for our purposes.</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">The problem that we are encountering is that periodically these devices must have their firmware updated and these updates are causing the UID sent in the DHCP request to be changed.</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">Here's an example of three entries taken from the dhcpd.leases file on the server:
<a href="http://pastebin.ca/2299463">http://pastebin.ca/2299463</a></font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">The first entry was was generated by a reboot early in the day.</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">The second entry was "control case" reboot made before we updated the firmware on the client device. Notice how it's identical to the first, with the exception of the times.</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">The third entry is after the firmware update. Notice that the MAC address remains the same, however the UID has changed, so the server issued it a new IP.</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">In consulting dhcpd.conf(5) I found "deny duplicates;" which sounded like a magic bullet workaround, so I added it to the subnet declaration in dhcpd.conf file, but the problem remains the same (in tests with other of the
same type devices and firmware upgrade scenario).</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">The server version is 4.2.4, running on FreeBSD v8.2-RELEASE. It's built via the ports system: isc-dhcp42-server-4.2.4_1</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">There is a DHCP-relay involved - it's configured on the VLAN interface of a Cisco Nexus 7010, running NX-OS v 5.2(3a).</font></div>
<div dir="ltr"><font face="tahoma"></font> </div>
<div dir="ltr"><font face="tahoma">Any insite would be appreciated.</font></div>
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<div class="PlainText">-G<br>
<br>
/*<br>
* Glen R. J. Neff<br>
* USD Lab Operations Infrastructure Team<br>
* glen.neff@emc.com<br>
*<br>
* EMC^2 == E^2<br>
*/</div>
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