Re-activate current lease on DHCPDISCOVER

[Drew Weaver]

-----Original Message-----
From: dhcp-users-bounce at isc.org [mailto:dhcp-users-bounce at isc.org] On Behalf Of Peter Breitenlohner
Sent: Thursday, October 09, 2008 10:16 AM
To: 'dhcp-users at isc.org'
Subject: RE: Re-activate current lease on DHCPDISCOVER

On Thu, 9 Oct 2008, Drew Weaver wrote:

> Maybe I didn't explain it very well.
>
> PC boots up once.
>
> Oct  9 08:06:24 c8 dhcpd: DHCPDISCOVER from 00:16:76:e0:d3:5b via 10.1.0.1.9
> Oct  9 08:06:25 c8 dhcpd: DHCPOFFER on 10.1.0.1.10 to 00:16:76:e0:d3:5b (lan-941a75b0) via 10.1.0.1.9
> Oct  9 08:06:25 c8 dhcpd: DHCPREQUEST for 10.1.0.1.10 from 00:16:76:e0:d3:5b (lan-941a75b0) via 10.1.0.1.9
> Oct  9 08:06:25 c8 dhcpd: DHCPACK on 10.1.0.1.10 to 00:16:76:e0:d3:5b (lan-941a75b0) via 10.1.0.1.9
>
> Some presses the 'reset' button on the PC.
>
> Oct  9 08:07:37 c8 dhcpd: DHCPDISCOVER from 00:16:76:e0:d3:5b via 10.1.0.1.9: network 10.1.0.1.8/29: no free leases
>
> My question is, why doesn't it just reassign the same lease that it already has? Obviously it isn't using it if it is requesting a lease.
>
> I tried the commands you suggested and it didn't seem to really solve the issue. Any more thoughts?

First of all, an RFC complient client should first ask for the same address
it got last time.

Nevertheless the server should offer the address it gave last time.

Could the failure to do so be due to the strange IP addresses you are using
(five digits instead of the usual four). Is that caused by some local
modifications?
--------

Oh whoops, I edited the IPs and I must've done a crappy job. They are actually regular IP addresses and how would a client such as a PXE client know what the DHCP address was previously?

That is actually the problem I'm having.

A PC boots up into the OS, it gets a lease then someone reboots the PC and boots it into the PXE loader then the PXE loader cannot get a lease anymore because the original lease was never released.

I'm just trying to get it to where the DHCP server will always reassign the lease if there is one valid each time the same MAC address requests it.

Normally I would just specify the hardware-address with the mac and make it fixed IP addresses but there are thousands of hosts and I haven't yet come up with a great way of tracking the IPs/MACs.

Thanks,
-Drew