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<p>Not quite answering your question but one way to restore some
order could be to give this one device a fixed address and perhaps
ask the server to not do pings for this device.<br>
</p>
<br>
<div class="moz-cite-prefix">On 16-10-2017 13.00, Dave Ca wrote:<br>
</div>
<blockquote type="cite"
cite="mid:trinity-0e09fce5-881d-4cef-ba19-ef33382c3e2a-1508151611885@3c-app-mailcom-lxa16">
<div style="font-family: Verdana;font-size: 12.0px;">
<div style="font-family: Verdana;font-size: 12.0px;">
<div>
<div>Hi</div>
<div> </div>
<div>I am running a failover pair</div>
<div>default-lease-time 43200;<br>
dynamic-bootp-lease-length 43200;</div>
<div>failover peer "failover" {<br>
max-response-delay 20;<br>
max-unacked-updates 10;<br>
load balance max seconds 3;<br>
mclt 300;<br>
split 128;<br>
}</div>
<div>I have a client that will repeatedly do a DHCPDISCOVER
at 50% lease time (rather than a renew), even when it
already has an address</div>
<div>in 4-3-6 this is how the flow goes :</div>
<div> </div>
<div>===</div>
<div>* client does discover</div>
<div>* server offers lease of 5 mins</div>
<div>after 2.5 mins :</div>
<div>* client does discover</div>
<div>* server pings previous IP it handed out to client</div>
<div>It gets a response (client is trying to do discover as
a way of renewing lease and has not released the old
address)</div>
<div>* server marks previous address as abandoned and
ignores client</div>
<div>* Client does discover</div>
<div>* server offers new address with lease time of 5 mins
(MCLT)</div>
<div>Then we loop round and start again</div>
<div>===</div>
<div> </div>
<div>I happened to have an old device at the back of a
cupboard with 4-1-1-p1 on it so just tried against that<br>
The result is the same, except it does not mark leases as
abandoned in the leases file so they get back into pool
quicker<br>
And also on the 4th DHCPDISCOVER the client does it gets a
12 hour lease for the same address offered on 3rd
DHCPDISCOVER.</div>
<div>Client packets are the same against both servers,
client never sends it's address in the DHCPDISOCVER packet
</div>
<div> </div>
<div>I know this client is behaving badly but I am not sure
what he expected dhcpd behaviour is, should it just keep<br>
letting the client eat through addresses or should it
treat it like a renew as the old version does (eventually
on 4th go) ?</div>
<div> </div>
<div>I know the server will start to use the addresses that
were abandoned when it runs out of new leases but<br>
would rather they didn't all get eaten up in the first
place. I am approaching the device vendor too but I</div>
<div>don't hold out much hope there.</div>
<div> </div>
<div>Thanks</div>
<div> </div>
<div>Dave</div>
</div>
</div>
</div>
<br>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Best regards
Sten Carlsen
No improvements come from shouting:
"MALE BOVINE MANURE!!!" </pre>
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