DHCPd sending lease expiration of 3600 seconds

David McKen david.mcken at mail.tt
Wed Feb 18 00:46:53 UTC 2009


Is it possible to ignore the clients requested lease time entirely?

Reason I ask is I would like to use the adaptive-lease-time-threshold 
option which relies on the min time.

David Forrest wrote:
> On Tue, 17 Feb 2009, Jeff Haran wrote:
>
>>> -----Original Message-----
>>> From: dhcp-users-bounces at lists.isc.org
>>> [mailto:dhcp-users-bounces at lists.isc.org] On Behalf Of Geoff Sweet
>>> Sent: Tuesday, February 17, 2009 3:47 PM
>>> To: dhcp-users at lists.isc.org
>>> Subject: DHCPd sending lease expiration of 3600 seconds
>>>
>>> On my CentOS 5.2 system I am setting up some network services for our
>>> corporate environment. DHCP works great EXCEPT that clients
>>> are getting
>>> a lease from the server that expires in 3600 second even though the
>>> config says otherwise. Here is my config:
>>>
>>> #####
> ---------> snipped
>>>
>>> # lease expiration
>>> default-lease-time 86400;
>>> max-lease-time 86400;
>
> ---->snipped
>>>
>>> I can see clearly in a WireShark network trace that the
>>> server responds back with the lease marked as expiring in 1
>>> hour. It's like the service is ignoring the default-lease and
>>> max-lease settings. Any thoughts?
>>>
>>> Thanks,
>>> Geoff Sweet
>>>
>>
>> I see something similar with dhcpd 4.0, except that my problem is trying
>> to get it to assign infinite leases.
>>
>> Wireshark showed dhcpd assigning long leases (I believe it was the
>> number of seconds until the Unix Epoch overflows 2^^31 seconds in 2038),
>> but I could not get it to assign leases of infinite length (all 1s in
>> the appropriate option value). This keeps the DHCP clients receiving
>> these leases executing but blocked on a long timeout in select() in
>> order to start renewing some day in the distant future when they could
>> otherwise terminate. The problem remains.
>>
>> I posted to this group, but never got a response.
>>
>> Jeff Haran
>> Brocade
>
> It seems sometimes the client requests a shorter lease.  If you want a 
> longer lease assigned than the client requests, just assign a min-lease
> like this:
> min-lease-time 85200;
>
> along with your max and default of 86400 and you'll get leases in the 
> window of 85200-86400.
>
>
> Dave
> St. Louis, Missouri
> _______________________________________________
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
>



More information about the dhcp-users mailing list