DHCP leases issue

Surya Teja suryateja042 at gmail.com
Sat Sep 7 03:47:42 UTC 2019


Hi Bill,

Thanks for reply as suggested i have increased lease time to one hour and I
observerd one more scenario when the client moves from one subnet to
another subnet ( lease time say 1hr). The client got IP from the second
subnet scope but the previous IP in the 1st subnet is still in hold and in
the lease file. It still recorded an active entry. How can the dhcp server
reclaims those unused IP's? Do we have any configuration statement making
dhcp to cross check all the active IP's of that scope before saying no free
leases.
The first IP is getting into free state after completing its 1 hour lease
duration till that time it is active mode only.

Thanks in advance.

On Sat, 7 Sep 2019, 00:33 Bill Shirley, <bill at c3po.polymerindustries.biz>
wrote:

> Note: two minutes (120 seconds) is a very short lease time.
>
> Are you sure you're looking at the correct lease file?  Your grep says you
> have *no*
> *leases* on 192.168.3.x.
>
> Your log entries via looks strange.  I would think it should contain the
> interface name:
> DHCPDISCOVER from 40:4e:36:d2:bf:9d via wifi
> DHCPDISCOVER from b4:18:d1:69:02:f9 (Bobs-iPhone) via wifi
>
> Bill
>
> On 9/6/2019 6:25 AM, Surya Teja wrote:
>
> Hi
> I have configured the dhcp on my local environment  with the configuration
> as
> =================================
> subnet 192.168.3.0 netmask 255.255.255.0 {
>         pool {
>                 range 192.168.3.3 192.168.3.143;
>         }
>                 default-lease-time 120;
>                 max-lease-time 120;
>                 option domain-name "example.com";
>                 option routers 192.168.3.1;
>                 option subnet-mask 255.255.255.0;
>         }
> But no client is able to get the IP and in the logs I can see:
> DHCPDISCOVER from 84:EF:18:6A:89:DE via 192.168.3.11: network
> 192.168.3.0/24:* no free leases*
> DHCPDISCOVER from 00:FF:4A:81:D5:A5 via 192.168.3.16: network
> 192.168.3.0/24: *no free leases*
> But it is not possible and none of the client get the lease from the
> specified network. I cross checked in the lease file also
> [root at dhcpserver]# cat dhcpd.leases | grep 192.168.3 -A 10 -B 10
> [root at dhcpserver]#
> It doesn't shows any entry
>
> Any help is appreciated thanks in advance
>
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