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<p class="MsoPlainText">Thank you. <o:p></o:p></p>
<p class="MsoPlainText">Please let me know if you would like to see more of the configuration, but for now I am including one subnet and client configuration block.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">class "Wired" {<o:p></o:p></p>
<p class="MsoPlainText"> match hardware;<o:p></o:p></p>
<p class="MsoPlainText">}<o:p></o:p></p>
<p class="MsoPlainText">class "Wireless" {<o:p></o:p></p>
<p class="MsoPlainText"> match hardware;<o:p></o:p></p>
<p class="MsoPlainText">}<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">shared-network "STUWIRELESS-XXX" {<o:p></o:p></p>
<p class="MsoPlainText"> authoritative;<o:p></o:p></p>
<p class="MsoPlainText"> subnet 10.31.0.0 netmask 255.255.240.0 {<o:p></o:p></p>
<p class="MsoPlainText"> pool {<o:p></o:p></p>
<p class="MsoPlainText"> allow members of "Wireless";<o:p></o:p></p>
<p class="MsoPlainText"> default-lease-time 3600; #1 hour<o:p></o:p></p>
<p class="MsoPlainText"> max-lease-time 3600;<o:p></o:p></p>
<p class="MsoPlainText"> option ntp-servers X.X.X.X, X.X.X.Y;<o:p></o:p></p>
<p class="MsoPlainText"> option domain-name-servers X.X.X.X, X.X.X.Y;<o:p></o:p></p>
<p class="MsoPlainText"> one-lease-per-client true;<o:p></o:p></p>
<p class="MsoPlainText"> option routers 10.31.0.1;<o:p></o:p></p>
<p class="MsoPlainText"> deny unknown-clients;<o:p></o:p></p>
<p class="MsoPlainText"> range 10.31.0.20 10.31.15.254;<o:p></o:p></p>
<p class="MsoPlainText"> }<o:p></o:p></p>
<p class="MsoPlainText"> }<o:p></o:p></p>
<p class="MsoPlainText">}<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">subclass "Wireless" 44:85:00:2F:81:86;<o:p></o:p></p>
<p class="MsoPlainText">host XXXX.STUDENT.XXX.XXX {<o:p></o:p></p>
<p class="MsoPlainText">hardware ethernet 44:85:00:2F:81:86;<o:p></o:p></p>
<p class="MsoPlainText">}<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Here is the logged output: <o:p></o:p></p>
<p class="MsoPlainText">Aug 23 07:52:56 srvr04 dhcpd: DHCPDISCOVER from 44:85:00:2f:81:86 via 10.31.0.1: network STUWIRELESS-XXX: no free leases<o:p></o:p></p>
<p class="MsoPlainText">Aug 23 07:53:00 srvr04 dhcpd: DHCPDISCOVER from 44:85:00:2f:81:86 via 10.31.0.1: network STUWIRELESS-XXX: no free leases<o:p></o:p></p>
<p class="MsoPlainText">Aug 23 07:53:09 srvr04 dhcpd: DHCPDISCOVER from 44:85:00:2f:81:86 via 10.31.0.1: network STUWIRELESS-XXX: no free leases<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Here is the lease status:<o:p></o:p></p>
<p class="MsoPlainText">Ranges:<o:p></o:p></p>
<p class="MsoPlainText">shared net name first ip last ip max cur percent touch t+c t+c perc<o:p></o:p></p>
<p class="MsoPlainText">STUWIRELESS-XXX 10.31.0.20 - 10.31.15.254 4075 436
<span style="color:red">10.699 </span>3639 4075 100.000<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">It appears I have plenty of IP addresses in this pool. It appears the look-up to match a known client is failing for some reason.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">BTW,<o:p></o:p></p>
<p class="MsoPlainText">I did clean-up a lot of dead host entries (cut the file size into 2/3rds of its original size), but still having the trouble.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Any help is appreciated. <o:p></o:p></p>
<p class="MsoPlainText">Thank you.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">-----Original Message-----<br>
From: dhcp-users [mailto:dhcp-users-bounces@lists.isc.org] On Behalf Of Simon Hobson<br>
Sent: Tuesday, August 23, 2016 2:29 AM<br>
To: Users of ISC DHCP <dhcp-users@lists.isc.org><br>
Subject: Re: Unknown client alerts and clients not getting IP addresses</p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">"Fleming, Tony" <<a href="mailto:t.fleming@tcu.edu"><span style="color:windowtext;text-decoration:none">t.fleming@tcu.edu</span></a>> wrote:<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">> Background:<o:p></o:p></p>
<p class="MsoPlainText">> We create a host record for each device that connects to our network<o:p></o:p></p>
<p class="MsoPlainText">> Over the years our dhcpd.conf file has grown due to
<o:p></o:p></p>
<p class="MsoPlainText">> little purging (yeah – I know we should be purging the data)<o:p></o:p></p>
<p class="MsoPlainText">> Symptom:<o:p></o:p></p>
<p class="MsoPlainText">> Suddenly today, we began getting reports users are unable to get an IP address.<o:p></o:p></p>
<p class="MsoPlainText">> The clients vary from iphones, to OS X and PC laptops<o:p></o:p></p>
<p class="MsoPlainText">> The issue doesn’t seem to be OS or hardware dependent<o:p></o:p></p>
<p class="MsoPlainText">> My logs are alerting:<o:p></o:p></p>
<p class="MsoPlainText">> dhcpd: DHCPDISCOVER FROM
<o:p></o:p></p>
<p class="MsoPlainText">> xx:xx:xx:xx:xx:xx via x.x.x.x: uknown client In my dhcpd file there is a “host” record for each device – so I am scratching my head to why the device isn’t getting an IP address.<o:p></o:p></p>
<p class="MsoPlainText">> Not all devices are having trouble getting IP leases<o:p></o:p></p>
<p class="MsoPlainText">> Workaround:<o:p></o:p></p>
<p class="MsoPlainText">> We have removed the directive in dhcpd.conf to “deny unknown clients”<o:p></o:p></p>
<p class="MsoPlainText">> Now all of our devices are getting IP addresses.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Post your config - not all of it ;-)<o:p></o:p></p>
<p class="MsoPlainText">But when you trim it, be very very careful that you don't alter the structure at all.<o:p></o:p></p>
<p class="MsoPlainText">Include a problem client - both it's config and the log entries for it.<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">_______________________________________________<o:p></o:p></p>
<p class="MsoPlainText">dhcp-users mailing list<o:p></o:p></p>
<p class="MsoPlainText"><a href="mailto:dhcp-users@lists.isc.org"><span style="color:windowtext;text-decoration:none">dhcp-users@lists.isc.org</span></a><o:p></o:p></p>
<p class="MsoPlainText"><a href="https://lists.isc.org/mailman/listinfo/dhcp-users"><span style="color:windowtext;text-decoration:none">https://lists.isc.org/mailman/listinfo/dhcp-users</span></a><o:p></o:p></p>
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