dhcpd mystery

[Les Mikesell]

Timothy Murphy wrote:
> Who or what decides the length of a dhcp lease?
> I notice that the computers accessing my desktop dhcpd server
> have widely different lease times.
> The laptop I'm currently using, for example,
> has a lease time of about half-an-hour
> according to /var/lib/dhclient/dhclient-eth1.leases:
> -----------------------------
>   renew 2 2008/1/29 13:08:12;
>   rebind 2 2008/1/29 13:34:10;
>   expire 2 2008/1/29 13:41:40;
> -----------------------------
> 
> But the server sets the time much longer,
> according to /etc/dhcpd.conf on my desktop:
> -----------------------------
>         default-lease-time 21600;
>         max-lease-time 43200;
> -----------------------------
> 
> Can the client change the lease times?
> Or is it entirely up to the server?
> 
> [My grand-daughter's Wii seems to have an even shorter lease time,
> at least it exchanges DHCPREQUEST/DHCPACK with the server every 2 minutes.]
> 
> Is there an online document that will instruct me on this?

The server sets an expiration time when it gives the IP and clients 
typically start to request renewals halfway to the expiration time but 
if they don't get a response, will keep using the IP up till expiration.

-- 
   Les Mikesell
    lesmikesell at gmail.com