Revoke a DHCP lease early?

[Daniel Feenberg]

On Sat, 9 Mar 2013, Modulok wrote:

> List,
>
> I'm running isc-dhcpd to serve leases to clients. Is there a way to expire a
> lease before it normally would, i.e. force a client to re-negotiate a lease
> early? Perhaps some shell command akin to the following (which would be nice,
> but obviously doesn't work)::
>
>    dhcpd --revoke 192.168.1.24

I am pretty sure there is no message the dhcp server can send to a client 
to request it give up its IP address unless the client has asked for an 
address or renewal. dhcpd is a server, it doesn't initiate commands. I 
expect that if you modified the entry in the dhcpd.conf file and 
restarted dhcpd that the client would be assigned (and use) a new address 
the next time it tried to renew (which is typically when half the lease 
has been used up).

My view tends to be confirmed here -

   http://www.cites.illinois.edu/ipam/leases.html

daniel feenberg

>
> How do you revoke a client's lease prematurely?
>
> Thanks.
> -Modulok-
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