howto configure DHCP to reject renewal of lease

Simon Hobson dhcp1 at
Wed Oct 11 15:50:30 UTC 2006

Gilbert XXXX wrote:

>is it possible to configure ISC DHCP v3.0.4 to stop renewing leases when the
>client attempts to renew its lease?
>From the dhcpd.conf man page:
>If the client thinks it has a valid lease and sends a DHCPREQUEST to
>initiate or renew that  lease,
>the server has only three choices - it can ignore the DHCPREQUEST, send
>a DHCPNAK to tell the client it should stop using the address, or  send
>a  DHCPACK,  telling  the  client to go ahead and use the address for a
>I'm interested in configuring the DHCP server to tell the client to stop
>using its current address when its lease time is being renewed (which
>usually occurs at T/2 if T = lease time).

No, it's not possible with the ISC server - it's not a configuration 
option because it's exactly the opposite of normal desired operation. 
You could fake something that approximates it by having a number of 
pools and a script that periodically changes them around so that the 
allowed addresses keep changing and others are barred - when a client 
attempts to renew an address that is currently barred it will be 
NACKed and will have to stop using it's lease.

But I'm curious as to why you would want to do this, it's VERY 
unfriendly to your network and will result in some seriously p***ed 
off users !

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