Theoretical Max Lease Time

Simon Hobson dhcp1 at
Thu Aug 31 12:00:56 UTC 2006

HAWKER, Dan wrote:

>What is the theoretical maximum lease time that you can set in DHCPD???

About 30 years I think, as in end time must be less than "now + 
2^31-1 seconds" and also less than the end of time as the system 
knows it (2^31-1 seconds after midnight 1st Jan 1970) which IIRC is 
sometime in 2036.

>I have a series of test VMware player machines a few of my developers use.
>The IP address and hostname is allocated dynamically by dhcpd using a class
>that matches VMware first 3 octets in its generated MAC addresses.
>They boot these VMs randomly via PXE, but what they boot changes as they
>develop a new package (automatic RPM/ANT build and a generated kickstart
>file). It'd be nice to be able to set the lease time fairly high to ensure
>they (within reason) always get the same IP address and hence hostname.

Bear in mind that should they change their client ID then they will 
still get a different address, and in the absence of a client id then 
the address will change with any change of virtual MAC address (are 
they random or static MAC addresses ?).


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