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On 11/17/2011 11:03 PM, <a class="moz-txt-link-abbreviated" href="mailto:scott_stone@trendmicro.com">scott_stone@trendmicro.com</a> wrote:
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<p class="MsoNormal">I'm having a lot of trouble finding
relevant information on this online, so I'm going to ask you
guys.. :)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have several thousand machines receiving
static host reservations with DHCPv4 currently. ie, <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">host myhostname.domainname {<o:p></o:p></p>
<p class="MsoNormal"> hardware ethernet
00:50:56:DE:AD:BE;<o:p></o:p></p>
<p class="MsoNormal"> fixed-address 10.0.0.1;<o:p></o:p></p>
<p class="MsoNormal"> option host-name
"myhostname.domainname";<o:p></o:p></p>
<p class="MsoNormal">}<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">... simple, right? OK, now we want to use
DHCPv6 as well as DHCPv4. It seems that the dhcp client
identifiers for DHCPv6 are *<b>arbitrary</b>*. Is there no
way to know ahead of time what they would be, since they're
not mapped to anything uniquely identifiable on the machine
(ie, MAC address)? Do I need to have someone manually
investigate all of these hosts to find their client
identifiers or is there something I'm missing here...?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">====================<o:p></o:p></p>
<p class="MsoNormal">Scott Stone
<a class="moz-txt-link-rfc2396E" href="mailto:scott_stone@trendmicro.com"><scott_stone@trendmicro.com></a><o:p></o:p></p>
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<br>
Not that I would think that this could really help ... It's just
that I've noticed that there's been this item in changelog to 4.2.0:<br>
- The 'hardware [ethernet|etc] ...;' parameter in host records has
been<br>
extended to attempt to match DHCPv6 clients by the last octets of
a<br>
DUID-LL or DUID-LLT provided by the client.<br>
<br>
I think it's the implementation of what David mentioned in<br>
<a class="moz-txt-link-freetext" href="https://lists.isc.org/pipermail/dhcp-users/2009-February/008092.html">https://lists.isc.org/pipermail/dhcp-users/2009-February/008092.html</a><br>
<br>
Also the following few lines were added in 4.2.0 to example
doc/dhcpd-dhcpv6.conf<br>
host otherclient {<br>
# This host entry is hopefully matched if the client
supplies a DUID-LL<br>
# or DUID-LLT containing this MAC address.<br>
hardware ethernet 01:00:80:a2:55:67;<br>
<br>
fixed-address6 3ffe:501:ffff:100::4321;<br>
}<br>
<br>
man dhclient says:<br>
By default, DHCPv6 dhclient creates an identifier based on the
link-layer address (DUID-LL) if it is running in stateless mode
(with -S, not requesting an address), or it creates an identifier
based on the link-layer address plus a timestamp (DUID-LLT) if it is
running in stateful mode (without -S, requesting an address).<br>
<br>
<br>
Just my two cents.<br>
--<br>
Jiri<br>
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