Best practice on removing IP Scopes(subnets)

Glenn Satchell Glenn.Satchell at
Sat Apr 25 02:03:30 UTC 2009

>To: Users of ISC DHCP <dhcp-users at>
>Subject: Re: Best practice on removing IP Scopes(subnets) 
>Date: Fri, 24 Apr 2009 11:54:35 CDT
>From: John Hascall <john at>
>Christof Chen writes:
>> I just want to mention there is a fairly recent addition to DHCPD:
>>     deny after TIME;
>> in a pool shortens the lease duration automatically as TIME approaches.
>> Together with a corresponding
>>     allow after TIME;
>> in a different pool this allows for a nearly automatic switchover at a
>> preconfigured time.
>That's pretty swell, but what would really be awesome is
>something which would allow renews, but not new offers
>in a pool!
>Maybe allowing "deny booting" in pool scope could do that.
>Then you could very nicely switch from one pool to another.

Note this is untested by me, but in theory something like this
in the pool, or subnet might do this:

if option dhcp-message-type = 1 {
	deny booting;


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