Configure Leasetime

Chinmaya S. Narayana Reddy chinmayareddy at
Wed Mar 29 20:08:32 UTC 2006

Here is the deal,

The clients/devices in my network would have to have different lease times.
For e.g, one device may have 1day, second say 1hour (both devices
are served by single DHCP).

My UI allows user to specify DHCP options to for each device.
I let user specify option 51 (dhcp-lease-time), which
user expects to be the lease-time for that device.

I understand lease-time decision made by Server. Question is,
can I trick server to force, the client, to use lease-time decided by user?
In the previous mail, you suggested use min, max to have same value.
I was wondering if I can force server to use value of option 51 as the
in offer and ack? Basically I need to understand the rules the server uses
decides the lease-time for offer/ack?

The reason we need to force the lease-time is, we want to study the exact
behavior of DHCP client in terms of lease renew.

chinmaya swaroop

On 3/29/06, Simon Hobson <dhcp at> wrote:
> Chinmaya S. Narayana Reddy wrote:
> >Quick question on this,
> >Can I force dhcp lease time, irrespective of what is declared globally
> and
> >what client requests,
> >by using option 51 for the particular host ? Reason is, my users can
> change
> >option 51 only !!
> What is it that you are trying to achieve ? The reason I ask is that
> I can't recall anyone wanting to do this before, I think most people
> just set default, min, & max lease times (sometimes by pool or class)
> and leave it at that.
> I doubt if you can set the lease time directly, it is calculated by
> the server. If you have control of the client then you can probably
> set what the client requests - but that is still bounded by min & max
> set on the server.
> Simon

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