Re: dhcpd(8) and unused or old MAC addresses

[Brett Lymn <blymn%internode.on.net@localhost>]

On Tue, Aug 22, 2023 at 09:41:48AM -0400, Greg Troxel wrote:
> 
> > Is there a way to "free" their entries, to let dhcpd(8) forget about
> > them, so that the relative IP addresses are re-usable? Each device
> > which receives an IP address is recorded in /var/db/dhcpd.leases. Is it
> > enough to manually delete its entry in that database file, or some
> > other operation is needed?
> 
> This works and I do it all the time.
> 

The lease time is supposed to control how quickly the IP addresses are
reused - half way through the lease time the client is supposed to renew
the address, if this happens then the lease time is restarted.  If the
client fails to renew the address and does not renew it at the expiry
time then the address will be reused.

So, you could reduce your lease time so ephemeral devices will get a
lease and it will be released quickly.  The balance being if you have
devices that you want having the same address are off for a while then
they may not get the same address again.  For those you could
statically assing a particular mac address an IP and have another
part of the range available for dynamic allocation.

-- 
Brett Lymn
--
Sent from my NetBSD device.

"We are were wolves",
"You mean werewolves?",
"No we were wolves, now we are something else entirely",
"Oh"