Maximum possible value for *-lease-time?

Glenn Satchell Glenn.Satchell at
Fri Jan 11 12:20:42 UTC 2008

>Date: Fri, 11 Jan 2008 12:59:31 +0100
>From: Emmanuel Halbwachs <Emmanuel.Halbwachs at>
>To: dhcp-users at
>Subject: Maximum possible value for *-lease-time?
>Hello everybody,
>I would like to know what is the maximum value possible for 
>  default-lease-time
>  max-lease-time
>E. g. is it correct to set it to value such 1296000 (15 days)?
>I didn't find the answer by googling or in the documentation. If by
>chance somebody has immediately the answer, I would be happy as I
>wouldn't have to dive in the code ;-)
>Emmanuel Halbwachs
>Resp. Réseau/Sécurité                    Observatoire de Paris-Meudon
>tel      : (+33)1 45 07 75 54                   5 Place Jules Janssen
>fax      : (+33)1 45 07 76 13                    F 92195 MEUDON CEDEX

It's a 32 bit number, so the maximum value is 2^32 - 1, but with an
absolute limit of that time in 2038 when the number of seconds since
the epoch reaches 2^32. So, it can be a really dig number, bigger than
you're likely to ever need.

If you have fairly static client list and a few spare IP addresses then
there is no reason why you couldn't lease times to be a few months, 15
days is entirely reasonable.



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