Question about DHCPRELEASE

Darren perl-list at
Fri Jul 28 00:37:43 UTC 2006

So, let me illustrate with example, and perhaps someone (*cough* David 
*cough* :) ) can tell if this is correct:
2006-07-27 00:00:00  client does DHCPDISCOVER
2006-07-27 00:00:00  server does DHCPOFFER of an IP Address with 
min/default/max lease length of 3600 seconds
2006-07-27 00:00:00  client does DHCPREQUEST for that IP Address with a 
3600 second lease.
2006-07-27 00:00:00  server does DHCPACK and creates 3600 secon lease 
for client of that IP Address
2006-07-27 00:30:00  client does DHCPREQUEST of that IP Address with a 
3600 second lease
2006-07-27 00:30:00  server does DHCPACK of that IP Address and updates 
the lease begin and end.
2006-07-27 00:33:27  client does DHCPRELEASE and removes the IP Address 
from its interface. The server subsequently destroys the lease and marks 
the IP Address as free upon receipt of this packet.

Is that the behavior that ISC DHCP v.3.0.4 will exhibit?

How does this behavior change in a failover situation, if at all?

Simon Hobson wrote:
> Darren wrote:
>> Does anyone know if DHCPRELEASE truncates the lease length to now() (ie:
>> does it end the lease)?  Or does it not modify the lease at all?
> It should result in the address being marked as free.

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