DHCP Addresses

[Jon M. Hanson]

On Thu, Mar 15, 2007 at 08:28:03AM -0700, Nathan Aubrey wrote:
> 
> Is there a way to force all connected machines to release and renew their ip 
> addresses from the dhcp server?
> 
> Say I needed to make a change right now, and I wanted to reqeust every machine 
> on the network to renew their ip without requesting everyone to reboot, is it 
> possible?

No one has to reboot to get a new DHCP address. In Windows you do the
following at a command prompt:

ipconfig /release
ipconfig /renew

In Linux you can either restart DHCPCD or just take the interface down
and bring it back up.

I don't think there is a way to force everyone to renew from the DHCP
server. How long are your default lease times? That would be the
worse-case scenario. So if you had 24 hour lease times you could do your
work late on Friday and then when everyone came in on Monday they would
have a new IP address. You could also change the default lease times
just before your DHCP server work to something really short but then you
would have to wait for the old lease times to expire before the new ones
took effect. The short lease times would make everyone request a new
address sooner. After you're sure everyone has their new IP address you
can change your default lease times back to a longer interval.